Quote Originally Posted by KizuyaKatogami View Post
I’d disagree with it not being talked up as a big concern. They mention it numerous times as if there’s something that’s going to happen in regards to it. I see it as plot armor because quite frankly yes it should’ve killed him. It would’ve been more believable of him to accomplish a feat like that if it was something like him exerting all his power at once. It wouldn’t be as big of a deal if they didn’t specifically mention it and show it. He even explains how it’s dangerous for him to go as far from the tower as he did when in Kholusia.
I think what you have confused is the proximity from the tower and the crystallization.

So the proximity from the tower becomes an issue of power, which is why he can't go to First and drive all the sinner eaters away himself and gets weakened when he uses his powers away from the tower. This is also why the Crystarium is a haven from Sinner Eaters because so close to the tower he has the power to drive them away.

He is dying, albeit slowly, because he used the crystal tower to artificially extend his life so he could be on the First when he summons the WOL. This process is turning him into crystal and will eventually kill him. This was a sacrifice he chose to travel in time and be present for Shadowbringers.