Simple: Observe in detail (Look for vampires in the crowd below. Still astrally perceiving.) What's the roll for that? Assensing + will or something crazy like that?
Assensing + Intuition. GM discretion whether any Perception modifiers (proximity, distractions, specifically looking, etc.) apply to Assensing rolls.
I had always assumed Perception modifiers applied, but I never thought to give the +2 for Specifically Looking. Still don't know how I feel about that one, as you're always Specifically Looking if you're Assensing something/someone.
We're going to go with this roll as it stands, and I'm going to continue to think.
In the crowd, Sister Rebecca sees 2 awakened, at pretty low levels, dancing away on the main floor. Overall, the impression is very jumbled in the astral right now. There's a lot of people down on the dance floor, and a lot of emotions, from chemically induced elation, to fear, to depression. From the railing, Becca can see the Yak guard still standing near the stairwell, and there are 3 figures putting off strong fight or flight responses who are approaching his position from various parts of the dance floor.
ETA: where can I find info on Gadreel so that I can plug its Initiative score?