If you combine fire with violence, it will explode! A fire, once full of violence, will surely explode. The fire can’t handle all that violence so the fire just rumbles and shakes and then finally explodes. BOOM!
As you watch the fire explode, you start to back (ばく) away. I don’t blame you. You need to back away or else you’ll get caught in the violent explosion. Back away a little more just to be safe.