I'd like to see /challenge fixed, becouse there are several bugs there.

1. when u are in a challenge, and u do /leave, nobody can fight until a server reset.
2. when you fight in challenge with explosive/suicide weapons (like rocket launcher, explosive packs, grenades) and u get suicide, the fight doesn't end until server reset
3. when being in the room of challenge (also /watch), you can use /gun, even in the challenge itself.
4. while challenging, you can do /visit to get away out of the ring, also from /watch


also in deathmatch you can use /visit to get away

*edit:
Never mind, i saw in the 'Other problems' section that these are done fixing and will be there in next patch