I think he would have a duty.
Let's look at it at a practical level. In an operational circumstance like this, the military police would not have the capacity to move out unaided by operational troops. If the operational commander says it's too dangerous and they're not providing support, at that point, under the current legislation, the military police members involved could perhaps raise an accusation or an allegation of interference, but presumably not. As I said, and I didn't mean it to be trite or tongue-in-cheek, I have never known military police or a police officer generally to be suicidal.