An eternity of drowning in a coffin seems like a pretty cruel punishment for something that's only been a threat. I can see people wanting to come up with contingency plans. We should have them for pretty much everyone who could possibly become a threat because of Lucifer's tricks. But these plans should be ways to contain someone until they're back to their right mind.
It's a hard decision to make. I say give everyone time to cool off and if they keep pushing for it then maybe make the decision then. As of right now it'd only add fuel to an already blazing fire.
Because they need something to focus on that they can actually hurt.