I turned on my anti-damage forcefield hack and killed him with my harpoon. That's how. On a more serious note, that's what happens when you try shooting someone using an elevator.
I got rid of that limit, a staff member could easily change it for me, they have my permission. Something that isnt a best round but is still clippable.
I guess that place is no longer unreachable since I was able to get there without propsurfing / player boosting