Princessa Bitchessa's Palace

In episode 4, Isadora Capri is noted to be both out of breath, and fidgeting anxiously with her jewelry when Wednesday runs into her near the end of her meeting with Fairburn, where she has just volunteered to go to Willow Hill to 'teach a music class.' This is her idea, and she has talked her way into a yes. Never, during crisis, during werewolf concerns for Enid, or being roasted by Wednesday, or any of the emergencies in the show, is Isadora seen anxious and fiddling with jewelry, except in regards to her trip to Willow Hill, and notably when Wednesday comes to her directly to ask for advice about Hydes. I read this initially as distress towards personal memories, but I don't think it is. I think it's anxiety towards being discovered, and not knowing if she should tell Wednesday anything or not. Evidence for this is that she changes her mind, and does tell Wednesday something. She describes her own experience in terms as similar to Wednesday's as possible: "I never knew his true nature" - "You fell in love with a monster" - "I only knew we were happy together." There is no denial or detail or agreement. Just very relatable terms mirrororing Wednesday's own experience. She knows very well Tyler and Wednesday's history, and has tried before to open up Wednesday to the idea of it being okay to lean into chaos and trust it, instead of only feeling safe with complete control.

After Wednesday is interested, she describes him being forced to attack her because of his master, not voluntarily, and her managing to fight him off, and then her distress at his death in the aftermath, and how he killed his master--something Tyler has just done. Wednesday instantly asks about if Hydes die without a master, and Capri confirms this and lists the horrifying and urgent symptoms--which push Wednesday further into the urgent drive to intercede before Tyler dies. I think that this scene is Capri trying to decide if Wednesday, who would be very helpful and is important to Tyler, can be trusted with information, and could change her mind about Hydes.

Circling back to Willow Hill, there's no way that Capri is unaware Wednesday is in the car with her. Not just because you can (especially in a tiny car) feel weight redistribute if someone climbs in your trunk (note this being instantly noticed in a much larger car later with the Norths when Agnes hides), but also because Capri is a werewolf, with heightened senses. She is actively (if seemingly 'unawarely') helpful in Wednesday sneaking in at the gate as well.

Once in Willow Hill, Capri is visibly anxious again and, despite being there to teach, immediately sits to play a song. She states before she does that she believes music can do things medicine cannot. If she really is just a werewolf, then all she does is play, but I don't think that she does. I think she’s picked up some more magical skills with her music.

Notably, the song she chooses is an instrumental iteration of The Cranberries' Zombie; an excellent choice both because of Isaac (who, notably Capri does not volunteer to teach at Willow Hill until immediately after the presence of in the facility), and because while a popular Halloween song, Zombie is actually about The Troubles, and less specifically about a history of ingrained violence and prejudice reducing some people's cognition to that comparable to a zombie, which costs the lives of many innocents, which the singer separates herself and her family from and refuses to be a part of. This applies very well to the treatment of Hydes in that world, and her personal stance on them and violence against them.

Coincidence?

Well, speaking of, it also seems wildly coincidental that during this song, Isaac breaks out of his cell. This is something we have seen him be strong enough to do before, so this could be a genuine coincidence, but it could not be. Last time was a woodshed. This is a secure facility. There's that old saying 'twice is a coincidence, three times is a pattern' for a reason. It is only during the song he makes any headway breaking his bonds, and escapes. It is also the moment the song ends that the alarms go off, something Capri does not look surprised by, and she seems oddly calmer than when she sat down to play. If she was actually nervous about going to Willow Hill, who on earth would be more nervous walking into an Asylum, than being in one when the security alarm blares? It's so perfectly timed, it's almost like her song ending set off the alarms.

Maybe that's just narrative pacing. Maybe it's just for how pretty it looks. Maybe she played 'Zombie' by the Cranberries and a zombie escaped and just happened to trigger the alarm the exact time she finished the song. Coincidences happen. Still, Capri leaves calmly, and is not seen for the remainder of the episode. Notably, this means we have no idea where she is after the song ends. Also notably, when the alarm sounds, she is seen in the background of the shot playing anxiously with jewelry until she hears the security guard say 'the zombie broke loose,' at which point she stops and looks composed. She does not look afraid when the alarms blare, she looks like she's trying to hide something.

By the time Thornhill reaches Tyler in solitary, the doors to his cell are already open, and the guards are mysteriously vanished. This means Tyler could have already left at any time, and has simply chosen not to. He was waiting. We have seen, in this same episode, that Tyler can snap the chains by transforming--he did the first time he attacked Thornhill. Without a guard to shock him into submission, the chains (the only thing he is still 'held' by), mean nothing. He's already free when Thornhill gets to him. This is objective fact. He's just doing what he does. He's acting, and he's waiting for her to come back, so he can kill her.

So why are the guards gone? Did they abandon their post because of the emergency? This seems unlikely, given his security risk and that he's free as soon as a guard isn't there. Possible, sure, if the guard is an idiot and doesn't do the one thing they're there for. Hell of a coincidence, and I believe that would make 4 coincidences now, and that's just inside Willow Hill proper.

Why are the doors open? The power outage? In security doors for confinement, when electricity goes out, usually electric doors deadbolt and cannot be un-locked, as a security measure. They do not open. Even if they coincidentally were unlocked because of the outage--let's say because of a health and safety code, they do not automatically open. They are manual doors. The final door is not electric at all. It's metal. It is also already open. This is an intentional, unarguably personally, physically done act, by someone.

And there is not a single other established character there that night who could have done it. Everyone else is either accounted for at the time (every named Willow Hill staff member, Louisa, Wednesday, Fester, Thing, Thornhill, Tyler's Mom) and confirmed to be somewhere else at the time, or wouls inarguably not have let him out (Agnes and Enid), or both (Isaac).

Someone did it, and it can only have been Capri.

It is in inarguable fact someone let him out, and the only named or even repeatedly seen on-screen character who had means, opportunity, and motive (or even just the first two), is Capri.

When Wednesday first meets Capri personally, she asks her why she's there, and Isadora says she decided to give back to her community. I don't think this is a lie. I just think it doesn't mean what it sounds like it means. At the end of the season, Agnes comments that Capri has vanished the second this all ended, and must have gone looking for a new job.

So why did Capri appear only when Tyler was jailed nearby, decide to teach a class at Willow Hill, help Wednesday get inside, and play Zombie the moment the security was breached by a zombie? Why was she there once and only once: the exact same three hour time window Tyler was set free by 'someone'? Why did she try to get Wednesday to relate to her and understand Hydes? Why did she vanish the moment she found Tyler?

Because she was only ever there for Tyler in the first place.

Her finale scene with Tyler is the most confident and comfortable Isadora Capri is seen the entire season. She is relaxed with Tyler, and open with him. She never seems threatened by Tyler; she is pleased in finally having achieved her goal, and experienced in how she approaches him. She offers him a chance, and lets him make his own choices and keep his own agency.

And she leaves with what she came for.

Anyway queen shit Billie Piper here in the background all season as Isadora Capri, the woman with an underground sanctuary network for Hydes, on a rescue mission she succeeded at.

Yes this evidence is indeed mostly circumstantial, but that is still evidence acceptable in a court of law, and the sheer amount of it is overwhelming. Most notably in the provable fact that no one else had opportunity, motive, and means to open the doors to Tyler's cell, which means it must have been her, and for her to have done so sucessfully in that time frame means, at bare minimum, she knew where to find him inside Willow Hill before she set foot on the grounds. And there are precious few reasons for her to know that, only one of which makes logical sense and lines up with the rest of the evidence on hand.