Rick, in uniform, did a sweep of the building on his way down to the ballroom, making sure there were no stragglers. He didn't want to leave anyone to whatever fate the Partners had in store for him. He also wanted to make sure there were plenty of eyes on the ballroom itself.
It occurred to him that maybe their hosts just wanted them all out of their rooms to plant something there while they weren't looking, but there wasn't much he could do about that unless someone had a way to tap into the security system. That was a bit out of his league.