We all know the heartache of seeing a love puppy or harmless little mewkat pop up in an arena or a "clear all monsters for the gate to drop/next wave to spawn" room. Like it or lump it, we need to put them down to move on.
It'd be nice if, instead, they'd already count as dead, or not count as part of the wave in the first place, so that we could leave them be and still progress in the level.
Wow, I thought they didn't count
http://imageshack.us/photo/my-images/716/spiral20111202171936.png/
Then maybe there is a bug or something there (I never left a red rover alive 'till the end on that room)