Having Grace allows you many opportunities humans (and most other things) don't have. It allows you to know just about every single person in a given radius and probably their BAC judging purely on molecules. It also allows you to know when time travel happened, because time travel's not an easy thing, even for angels to pull off and Gabriel gets slammed with the sudden time displacement harder than most, because he wasn't expecting it.

The minute he shakes himself out of it, he hears Ahiru's voice and goes to her. "Kiddo? Kiddo. If you get yourself trampled, so help me-"

He sounds more desperate than angry. It's a big field, but there's a lot of inebriated and unhappy people around here.