The DM was hired to be a buddy to the missing woman. That carries responsibilities. No punishment for failure to perform, but the responsibilities are there.
The DM surfaced and then went to be by herself, it has been stated she was in shock. OK, now what? She cannot handle the stress of seeing a diver lost and still perform as a DM. It's time to do a gut check and stop being a DM. She did not aggressively pursue the victim, it seems she was "waved off" and stopped. Not good in a rescue scenario. She has now demonstrated she cannot handle the job, and furthermore, when she got to the surface she did not function in an acceptable, professional manner. Time to hang up the DM cap.
Harsh, but accurate.