There's nothing like trivialising what could potentially be a nasty accident by putting a bit of Mario music over the top so we can all have a good chuckle. After all, what's the internet for if not to push the boundaries of bad taste.
Just because they're one of the few humans to ever set foot on the surface of the moon doesn't mean that they'll be able to keep their balance. Maybe someone tied their moonboot's laces together or something?
Do you ever have one of those moments in life when things don't go quite to plan and out of nowhere a fairly safe and ordinary situation turns bad very quickly, leaving you in a world if FAIL. These are those moments.