What SM said. The human body can be unusually frail sometimes and incredibly tough. I know a girl who broke her foot stepping off a curb. On the flip side a guy fell 40 something feet after his bungee cord snapped and only had a dislocated shoulder and a slight neck injury. We've all heard of muscly types like fifty cent survivng point blank gunshot wounds. Even one of Saddam's sons had been shot 17 times in a failed assassination attempt before he was killed by Allied forces and survived.
Also, having boxed against heavier opponents from different weight classes (I was a welterweight training against a group that developed heavy weight talent) some of that stuff can be deceiving. When your tired opponents lock up. The heavyweights being much bigger and stronger would simply push me out of the way, and I'd go airborne because I was riding the momentum of her push.
Lex might not have been struck as much as lifted and flung by the momentum of the movement of Gill's attack.
The striking the pillar thing was probably more about angles than anything else. If it hit the meat of her back and not her spine, she'd probably be alright.
Or as somebody already said, movie magic.
