Besides which, you're still failing to note that even with your character running backwards (which incidentally wouldn't make much difference as your rocket flies so fast, and would take fractions of a second to cover fifteen feet (the halfway point your insisting it reached) he's still incredibly close to an -explosion-. I'm assuming you didn't note in your sheet a resistance to loud noises, so with even normal human hearing you should be only able to hear the dull ringing of explosion.