This is called "Tactics and Training" My take is this: If you say, "I have a bomb", that is a direct threat on my life,,,,just the same as pointing a gun at me or people I love,,,,Threat eliminated.
While we are sitting here in our nice homes,,,,playing scenarios and second guessing,,,,he made a decision,,,,if you can't make a decision,,,,immediately and with conviction,,,,you are better off leaving your gun at home. Your indecision will get more people killed than taking action,,,if you all tossing out that he could have triggered the bomb,,,,he could have done it anyway or it could have gone off inadvertenly as many homemade bombs do.
My final point is this,,,,get the mindset to be able to act so if you haveto you can!!!!! If you spend too much time thinking about collateral damage,,,,that's what you will get.