Thank God! Smoonee with brains speaks!
Falling off the tower killed Ansom, a level 10 Chief Warlord, but not Bogroll, a twoll with 12 hits. Did the fall strike less than 12 hits from Bogroll? If Ansom died first, and the ensuing 2 levels gained to Bogroll by his death, gave Bogroll enough additional hits to survive? Source of defense is also important. Ansom's was derived at least partially by armour, which would be a hindrance on landing, whereas Bogroll seems to not wear armour, suggesting his thick skin is providing the defense value. Bogroll may also have had a soft landing on Ansom's (very recently) croaked corpse. Its also noteworthy that Ansom had already received some considerable damages in the battle thus far, so it is likely his hits were lower then they would be when completely healed. It is possible that since Ansom landed first and Bogroll landed on him Ansom took a larger share of the falling damage.