If rage could trigger his transformations, Remus might never have been fully human again. He'd seen red when they found Sirius, bound and broken by his family who should have cared for him and protected him. Worse, by his brother – his brother whom they'd trusted, whom Remus had loved – who had somehow weaseled is way into their hearts only to betray them the very moment they'd been foolish enough to let their guards down.

Never again.

Had he been able to transform without the power of the full moon, he'd have changed in a heartbeat; he'd have sniffed out both of the vile Death Eaters and shown them the true meaning of blood lust.

As it were, Remus simply made a vow: he vowed never again to be deceived; never again to let his emotions cloud his better judgement; never again to let someone in so far that they could ruin him like this – break his heart and hurt his friends (his fault). Above all else, he vowed never again to leave Sirius vulnerable. He'd let his friend down, and that was as despicable as if he'd cast the spells himself.

And so he stood guard in the private room in St. Mungo's, stalking back and forth like a caged animal between Sirius' bed and the door. He itched to take action, but refused to so much as take a seat until Sirius was out of danger.