From Stencylpedia:
While loop
"Runs the wrapped blocks while the given condition is true. If the condition is false to begin with, nothing will run. Make sure that the condition becomes false at some point during the evaluation of the loop (or use the exit loop block), otherwise it will result in an infinite loop that will crash your game."
Just place the point reduction in the bomb's behavior. You can use the trigger block to trigger an event for your scene behavior that manages points, for example.