When Irahl goes to move his glass of ice aside, he takes a quick moment to jingle the cubes around without even thinking about it. Maybe an idle gesture while thinking; maybe subconsciously wanting to start chomping on those bad boys.

For now, this glass gets pushed aside with the other one, waiting in the wings.

"Why? ...Afraid you'll trip and end up outside, twenty floors up?"

He really does have to just make a guess at Vincent's reasoning here, since all glass buildings do for him is make his sniping work easier.