When Dylan reached the hospital, most of the scene was cleared up. He still needed Cali's help to get inside. But when he reached the door of Darren's room, he stopped. He couldn't bring himself to open the door. It was like someone nailed him right there.
On the way to his room, Cali had detailed him about everything that happened since her last visit and it left Dylan shaken. So much happened and he didn't know any of it. Just because he was trying to gather his strength to face his friend, he actually didn't even realize that his friend was in such grave danger.
