Is there not some laws that require a mariner to render reasonable aid when there is a life or death situation (assuming that this does not endanger themselves or anyone else). The doctor defintely knew he hit a diver and decided to take a quick look and then leave. No offer to help, no radio contact, nothing but leave the scene.
I think this is analogous to a doctor deliberately driving his vehicle off a roadway onto a sidewalk, driving over a pedestrian at a high rate of speed and then immediately leaving the scene.