#orphell

We see that when Deon informs Orphell of the current situation in the Tower, he's particularly responsive to matters concerning Kielnode.

This is possibly because he feels some loyalty for Kielnode as someone his senior in both being in the Tower and leaving it, and the person who motivated him to take the right course of action.

So it is quite possible that after exiting his room... he specifically went to search for Kielnode.

And how would he go about doing that?

By following the scent of his blood.

We saw back in Ishuella that Orphell seems to have a keen sense of smell, especially where blood in involved, to the degree he is able to pick up on the scent of any blood in the entire area.

Kielnode was clearly greatly injured from his tortures, and Deon's report itself infers this. So Orphell quite possibly followed the smell of his blood to track where he was taken, and by whom.

Following the scent of Kielnode's blood leads Orphell to find the culprit at the end of the trail.

Lispen is presumably on the balcony he flew off of with Kielnode to chain him to the cliffside, which is ultimately where the trail of blood would have ended inside the Tower.