I just ran into a succubus and an evil eye. The succubus became a wraith when I killed it. The evil eye then fought against the wraith and shot at it, but they often just evade it and don’t take any damage. Then I killed it with my corrupting glaive.
My setup is neat for these floors. Wand of Prismatic Lightning gives me sight in the dark dungeons and renders evil eyes and scorpions basically harmless when it blinds them. That wand is only +1, but my Staff of Magic Missile +15 can give it quite some punch. For scorpion that means I have to tank one projectile, but evil eye charges slower. Though that wand is directly followed by Wand of Frost in effectiveness, which makes it for scorpions impossible to escape melee and evil eyes charge long enough to hit them twice and run away.
No, I can go on exploring the floor and then go to that room when I’m back at the entrance … or go there when I’m out of staff charges.
edit: No, I’m wrong. It only feels like taking longer, but the detour would take more turns. Unless I have to wait for my staff to recharge anyways.