John has a flashback in the hospital and takes someone hostage.

[melodyunity.livejournal.com]

I posted this over at sherlock_search about a month ago, but I still haven't found the story, so I'm posting it here too. It's a BBC Sherlock story.

I'm looking for a story that has John in the hospital. While he's there, he has a PTSD-related flashback, and I think he ends up taking a doctor hostage? Someone hostage, anyway. Sherlock finds him on the roof and talks him down.