I'm not sure I support this one myself, considering how undoomish it is, but I had it in mind for a while:
A short hallway started at the center of the left wall, leading into a wide, screen-high room to the right, full of SS-nazis [this part's inspired by a suggestion on the wiki] - these are effectively captains with damage and to-hit bonuses which make them an actual threat.
Them dealt with, there's another hallway to the right of the level, leading to an item - Dopefish Steak, a consumable Inv. Glode, considering the Dopefish was itself invulnerable ("swim, swim, hungry" :) ). To prevent it from making full wins too common, trying to activate a nuke under the influence notes that you're too dopey to work it.
It's there regardless of kills, and if you feel like running through under fire, taking it, and running back under fire, you theoretically can. That means cowardly hellrunners with good armor on a kill-less game can use this level well, or if you're playing on N!.
I wouldn't have posted this if not for LS and the AoD, and the fact that this is Hell's Museum with appropriate relics of the past and other worlds.
This room, if placed far enough into the game, will also help deal with some of the 10mm ammo issues.