There is a common law concept known as “felony murder” where a co-conspirator can be charged with murder. If you and I plan to rob a liquor store, and you’re sitting in the car when I go in, if I get in a scuffle with the clerk and kill him you could be charged with felony murder even though it was not part of the plan and you were in the car.
Having said that, it’s unlikely here for a number of reasons I think. And I’m going from memory back in law school which was many many moons ago.
As far as giving up names, there is an old adage that “the first to squeal gets the deal.” But it usually requires turning over someone further up the chain, or giving an unusual amount of help.
I have only tried a few criminal cases though, usually against my will. So there are others who have better info here I bet.