Imagine casually walking into that room with a sledge hammer and sneaking up behind this girl, raising the hammer above your head, and with all your might, slamming it directly onto her upper back, crushing her spine and paralyzing her then screaming bloody murder and running at everyone else at the gym until they scatter out of the gym - this girl's wails and cries echoing off the walls, as everyone else scrambles for the door. Then locking the gym door and slowly making your way back to this girl, as she twitches and breathes in agony, then beating her head in with your fists until she is barely conscious, stripping her pants off, positioning her limp legs wide open and then forcing the sledge hammer handle into her pussy all the way up until it can't go any further. I'd drag her body, hammer still in pussy, all the way to the front door where people helplessly watched. I'd position her bottom so they could see the hammer handle sticking out of her pussy and then go get a dumbbell, flip her onto her stomach, and position it under her face then make her bite onto the dumbell handle. I'd pull sledge hammer out of her pussy, slap her ass a few times to get a good feel of it, raise the hammer above my head again, and then bring it down as hard as I could to the back of her head, American History X style, crushing her skull in front of whoever was brave enough to watch from outside. I'd then reach into her gashed open skull and grab as much brain matter as I could, open the door, and run at the people outside - trying to smear as much of it on them as I could.