Figuring out the rest means finding a suitable ambush point.

Easier said than done, perhaps. At first glance, Ellis had thought it easy, but now—

"Behind those drapes," is the hissed instruction for Wysteria. Yes, Ellis understands that two voices answered Tony, both full of confused concern. It is clear his intent is to flatten himself against the wall, trust the shadows and narrowed perception of the incoming guards to do the rest of the work necessary to secure the element of surprise for him.