I had to kick two people out of a ruptured AAA once. The PCA from PACU took it upon himself to bring the unit secretary to the room so they both could watch. As it was, there were too many people in the room, so I told him they both had to leave. He actually tried to fight with me- saying he'd been in to observe before and no one else had ever complained. I still kicked them out, and he tried to have me written up for it. He eventually ended up getting fired (not for this, for multiple other issues). I say, if you aren't needed (maybe if we'd needed someone to act as a blood/lab runner), didn't even ask permission, and it's already crazy with extra people (additional surgeon, extra surg tech to help with retraction, additional circulator to help anesthesia with checking blood, circulating anesthesiologist overseeing multiple rooms but spending most of it in this one, CRNA, and anesthesia tech), then you just don't belong.