Swamped

You can't have raised his suspicions that long ago, considering how freely he was talking. But you didn't bring up the supposed problem right away - that might have made him wary.

Well, you have a plan if he is testing you.

"You think I didn't already do that? That's why I'm out here looking for anything to give us an edge, I've got orders to. I thought your little pet might fit the bill."

"Funny," Setrus sneers. "Bird would have asked you to find me. So. Who are you, and where did you get mask?"

The moment he finishes asking, he collapses. So you are looking for a "bird" of some sort. And Mortimer might have a clue as to who that means.

But you can't relax yet - Nocta's still moving, and she's got her eye on you. And Mortimer's gesturing suggests he doesn't have another dart for her.

So you're going to have to handle this yourself.