I recall Piranha mentioning that if your hero dies in a ruin that what ever he killed would be dead when the next hero entered the ruin.
In a game 4143 (Smash Round 2) I entered a L1 ruin with a DK and a Ghost and encountered 3 skeletons. My hero killed 2 before he died. I had a Paladin in the stack and immediately sent in the Paladin to finish off the last skeleton. To my surprise there were 3 skeletons in the ruin which my hero killed.
KGB