Make the Obsidian Crown disable all healing

[Weavel]

Idea: Holy water disrupts the crown's powers for however long it's in the person's blood, enabling a swift toolboxing.

the crown flushes your bloodstream permanently

Water the floor, weld the crown clown in a locker after he slips, space/incinerate/gib him.

Get the AI to help and electrify a door before having it crush him. Repeatedly.

he is not stunned long enough by a riot shotgun to get a second shot in, I would be surprised if he falls at all from water or electricity

Spray him with a hellfire mix and watch him burn alive.

probably not an awful idea

Force feed him a rainbow melon slice and hope it blows up in his (and your) face.

You can't interact or you teleport away instantly, might not happen with food but he could simply move away

Have the mechanics set up a bunch of launchers in the hall and fling fifty floor tiles at him as you chase him down.

this sounds hilarious and I want it to eventually happen

I don't know why I wanted to reply to each suggestion but there you are, he just can't be stunned or damaged fast enough unfortunately