There is only one way forward and this is it.

I think they’re both going to die, and I think Eve will probably be a suicide. Not sure on Villanelle. 

Some relevant quotes and references:

Eve, Season 1 kitchen scene. “I’m going to find the thing you care about, and I’m going to kill it.”

Eve, on the bridge. “Help me. Help me make it stop... You’re going to tell me to jump?”

Konstantin, to Eve 4x01: “You’re going to die, you know? Whatever this is, you won’t come out of it. / Thank God.” 

Eve, on the scooter. “Look, l know this is going to end badly.”

Yusuf, post karaoke breakdown. “My last tour was hard. Seven of us came back, there’s three left.”

Eve, post karaoke breakdown. “What if I can’t move on? But what if I don’t want to?”

Eve, to Martin. “And unbelievably, I survived! ...For what? For what? What does it matter if the cells keep dividing and its endless?”

Konstantin. “Whatever you’re going to do, Eve, don’t do it alone.”

Cupid and Psyche. In the mythological story, Psyche has to enter the underworld to complete one of the tasks given to her by Venus. She climbs a tall tower and prepares to jump off, killing herself, before the tower reveals instructions for an alternative way into the underworld. After completing this final trial, Cupid convinces Zeus to give Psyche ambrosia, making her immortal, so they can be united as equals.

The fish tank is a visual reference of the 1996 Romeo + Juliet movie.

Villanelle / Jesus connection. You could read a lot of things into this, but at a basic level.... he dead.

Of these, I think the bridge discussion stands out because it shows she was thinking about suicide already back in season 3. Villanelle is all she has left, and if Villanelle is dying or killed then what’s there left to live for?

Now that they’ve brought back Irina and highlighted both her employment by the twelve and her personal grudge toward Villanelle, it seems inevitable she’s going to be taking a shot at Villanelle in the finale. It’s a small tragedy among many other tragedies that Irina is now going to be working for the organization that killed her father.

I can easily see Villanelle being mortally wounded by Irina and Eve deciding to join her in death. Maybe it’ll be a throwback to the moment in Season 1 where Villanelle and Eve knowingly meet for the first time. The moment when Villanelle holds the gun to her chin in a mock suicide gesture and Eve screams “No!!” But this time Eve will do it anyway, because what’s more romantic to our murder wives than dying in each others arms?

I would almost bet money on this, especially because of all the other Season 1 callbacks we got in 4x07 (Eve with the shopping bags looking like V, karaoke flashback, etc). How can Eve survive without Villanelle? We saw in Episode 7 that Eve is devastated by what her life has become and Villanelle is all she has left, if she even has that. There are no true happy endings left for Eve, although I expect some soft moments before the end.