I think even if the bombs had gone off, shit would have gone sideways for them no matter what. One: they would be shot dead by police. Although despite their writings I don't really believe that they actually wanted to die by cop because they ultimately wanted autonomy over their own lives and suicide was the only way to do that. As to where, I'm not sure. Possibly behind a parked car during a shoot out after being wounded? Running off into the neighborhood, splitting up out of panic, and doing away with themselves in someone's backyard or in an alleyway? Who knows.
Two: the more likely scenario in my head - they would have been too close to the blast radius while waiting outside for the students and been killed or injured by debris and projectiles. Best case scenario (for justice, anyway) they'd be rendered unconscious by the force of the explosion and then possibly taken alive.