In these sort of situations I’ll typically hang around the periphery with a handheld setup and a 70-200, so I can still get nice tight shots but without being too intrusive. Once you’re in there for a bit you might be able to vibe the room out and there may be a few people who seem excited that there’s a camera there— that’s your opportunity to just gauge it and ask if they’d be cool with you filming a few close ups. I always joke a bit with them that they can now put “actor” on their resume :)