I'm not sure Limbo/Mortuary are the best places for an AoMr, but anyway, what could you do ?
Shoot, of course !
*With the insane damages of a sharpshooter, viles go down very fast, and so do their summons. (shoot viles first, btw)
*Equipping an ammo box to avoid dying during reloads is a good idea.
*Usually, having one or two hatred skulls helps a lot for mortuary (clear corpse, but also makes you berserk, which is a huge buff in speed and resistances, giving you much more time before you need to consume medkiits or supercharges.) Blood skulls are not that useful. Fire skulls suck (well, they still clear corpse, but I don't think they are worth an inventory slot, except if recently buffed.)
*Go asap in the upper right to get the nuclear BFG for clearing enemies & corpses (not a valid choice in AoMr, of course, but it's usually what I do in normal runs). Harder in Limbo too, since floor is quite hot :)
Other alternatives include leaving the level, nuking it, dying in, or making a save when entering, so you can train and understand how it works (I was really too much ****** off by improved Chain courts as AoMr, so after 5 or more promising chars dead here, I just switched to training mode, and after many attemps (50 ?), including more and more successful ones as I was playing, I continued my game (and made it !).