Downpour is Episode 1-7 of Trauma Center: Under the Knife and Second Opinion. It's a story-only episode.
Story[]
The episode begins with Dr. Hoffman reviewing Derek's decision regarding the previous patient. While he was basing his judgment on limited information, he had essentially missed important memos from the lab regarding the patient's condition, and dumped his responsibilities on Angie. Angie enters the conversation and calls Derek out for his negligent behavior. She also says that "he's not a real doctor" causing him to leave Hope temporarily.
Later that day, Derek is sulking as he walks downtown, feeling that he's failed as a doctor. He then hears of a nearby car accident, and works out that they'll be transferred to Hope which doesn't have anyone on call at the moment. Without a moment to lose, he rushes back to Hope and prepares to get to work.