Castiel manages until 40 before his legs give out underneath him and his voice breaks on an already hoarse cry, throat raw and cheeks wet with tears. "I'm sorry," he mutters, two, three times with a broken voice, struggling to get his trembling legs to carry his weight again instead of the rings above his head. "I can... I'm... I'm good..." But he isn't. Castiel is in pain, emotionally more devastating even than the physical, although right now both pains are fairly evenly matched. And he can't admit failure, doesn't want Sam's anger, doesn't want his safe word or another provocation, just wants to do something right, see something through that'll allow him to feel like he earned forgiveness, like he deserves it.