YEah, one time my DM designed a double room (one set of double doors that open to two different rooms (which are side by side)). I was playing a bad ass aasimar sorcerer, Yan-san.
Yan-san and the cleric enter the room on the right- meanwhile the shadow dancer, and two war-forged juggernauts enter the room to the left.
And what do Yan-san and the cleric see? A beholder- awesome. What do the BMX bandits see? A lich- sooper awesome.
The beholder uses his save or die beam on the cleric- who then dies. The lich immobilizes the BMX bandits. The beholder attempts to use the same beams of death on Yan-San Poophands Dragon's Bane, but his reflect spell causes instant death to the beholder instead. Great, 1 for 1.
The lich casts sleep on the BMX bandits and they are out of the fight. Yan-san then used gaseous form to creep into the other room and chose to use my own save or die spell on the lich- to make a long story short Yan-san summoned a horde of angels while everyone else died, or fell asleep.