Gadriel nods sagely. "That is the problem: the Archenemy is cunning. Many may have fallen to Chaos inadvertently." He looks around again, because Chaplains are creepy and could appear anywhere. "I myself nearly fell prey to Chaos. It directed me to murder my superior officer." He's confessing and that's good for the soul, right?

Also, see, if it could happen to him, it could happen to anyone.