Board Thread:Arrow discussions/@comment-9346948-20161103005621/@comment-27097330-20161105000613

Kir the Wizard wrote: Thea and the disarmed guard were there. They'd be the ones calling the hospital. Once in hospital, the ACU team would escort Chance away, explaining the situation and telling the doctors to keep their mouths shut on behalf of the Mayor Administration and releasing a fake autopsy report as part of the secret plan to lure out Church's criminal Trust.

See also: how Billy Malone has been texting Felicity about his new job on ACU the whole episode. But you have no way of knowing that. It's an important plot detail that was skipped.