Rumble never been dropped I don't think, pretty much impeccable defense on the feet, maybe he was rocked in the Vitor fight but he shouldnt have been fighting at all that night.
Hasn't taken to many beatings because he usually mentally checks out if he's losing and gives up his neck long before, which to his credit probably spared him alot of uneccessary damage throughout his career.
Plus he's been in there with some dangerous guys like Glover, Arlovski, Vitor, Gustaffson, Manuwa, Bader, Cormier X2 etc.