Earlier quoted context omitted.
May SWAT team guns shouldn't have independent triggers, but require some kind of consensus algorithm across SWAT team members for a pulled trigger to have an effect.
Wow, I can imagine that going wrong in so many ways. Executions squads come to mind. Groupthink. Even less liability. Instant guaranteed kill instead of only probably kill, even fewer annoying survivors in court.
I think under those circumstances, having a consensus algorithm in place would diminish the likelihood of it occurring, since, presumably multiple agents would have to have the fear reflex at the same moment. Unless agents are getting feedback from others about their trigger pools, or decide before hand that they are going to do it all together, I just don't see the scenarios you describe being realized. Of course, if cops go in with the idea that they are gonna kill someone, then they are no longer behaving lawfully.
My real issue with the idea is how practical it would be. If an officer's gun didn't go off when it should have, and they were killed, then people are going to be really upset.