I clearly remember the "immunity" requirement. However, I don't believe that Obama would allow any "pressure" from the military. But then, that may be why he fired so many top brass. Geeze, I hate giving him ANY credit for anything, and I'm still not certain why that is why he didn't insist while in a position of absolute power that "immunity" would be non-negotiable.
It wasn’t just the military brass. Even the leftist lawyers that littered his administration would have told him the same thing. You can’t leave military personnel in a combat role in a sovereign nation without having a clear agreement on their legal status. Sending soldiers into that kind of environment is an invitation for a large-scale mutiny.