It was almost an hour before she had calmed him down enough for her to leave. She walked out of the room, turned a corner and then sank to the floor against the wall. He was right. She had put Sherlock in danger. She didn't like their father, he gave her the creeps. What had she done?
Mycroft was formulating a plan. The nighttime rounds happened at 10.30. After that, the shift ended, and there was one nurse and a junior doctor on his ward. That was the best time to sneak away, as they wouldn't miss him until the morning rounds at 7. By that time, he would have rescued Sherlock. He waited until 10.45 before he got up, went to the wardrobe and took out his clothes. He got changed silently, as he was used to doing, and left his shoes off, carrying them dangling by the laces. Completely silently, used to sneaking around, Mycroft left his room. Checking for staff members, he made his way towards the stairwell. He knew that several of the nurses went to smoke at night half way down between the fourth and third floors, so he couldn't go down the stairs. He went up instead, all the way to the top of the building. There was a key code to get up to the roof, which he hacked through in two attempts based on the wearing on the numbers. On the other side of the roof was an outside fire escape, and he ran down that as quietly as he could. When he reached the ground, he doubled back to the side ally where the hospital bins were emptied and slipped on his shoes. He went out, back slouched and hands in the pockets of his grey hoodie, and vanished expertly into the crowd.