In the wake of John's response, Will can't help but think of the scenario he'd just left. Hannibal and himself, two men who had tried countless times to kill one another, teaming so seamlessly together to take down Dolarhyde.

"So often our enemies end up being our strongest allies. Especially when it comes to a greater, mutual threat," he speaks so softly he is probably making the remark more to himself than directly to John. But to ears as well trained and keen as John's? Reese can probably observe that Will is definitely speaking from experience. "An enemy often knows you better than a friend."