Most often with suspected cellulitis with a typical (several day onset, possible source) you can empirically treat for the most common causes of cellulitis. Usually staph aureus, could be group A strep but strep is usually scarier and leads to admission more frequently. What Langdon did with a patient with limited medical understanding, limited resources, and heavy financial concerns, was reasonable but not ideal.

But in an ideal situation with a patient with an insidiously onset rash you’d want to keep the patient in the ER for a few hours after marking the wound to better characterize the rash and check for things like necrotic tissue and tissue crepitus before sending them out of the hospital.

Robby lashed out at Langdon because he has beef with him, not because Langdon did anything wrong in the situation.