Her anxieties aside, it doesn't take Joan too terribly long to fall asleep, feeling comforted by Ted's breathing and warmth, as well as Sherlock's vigilance. As her breathing slows, Sherlock leans forth slightly, his attention sharpening further as he watches for a seizure to set in at the same point it had twice before.

The minutes tick by slowly.

Nothing happens.

At half an hour Sherlock lets out a relieved sigh and relaxes.