Factual error: Derek performs CPR on Meredith in the back of the ambulance, but he does so incorrectly. He gives one breath and five compressions instead of two and thirty. Also, drowning victims need oxygen, and Derek should have used a BVM to ventilate Meredith, not mouth to mouth. Any doctor would have known how to provide proper treatment.
Grey's Anatomy (2005)
1 mistake in Drowning on Dry Land - chronological order
Katie Bryce: My head is full.
Dr. Meredith Grey: It's called thinking. Go with it.