We do not know what happedned while C-chan was inside his coffin. Maybe he made his innocence leave his body, maybe it did it itself. We only know that after that he had controll over innocence.Who knows what that is. I suspect that this is a different example - that was another manifestation of Crowley's Innocence, but he was still controlling it. Allen and Rinari had NO control over their Innocence when it saved them numerous times. Presumably, if Crowley didn't want to fight, he didn't have to. The others didn't have that choice.
He had to. He wanted to protect his friends after all.