During an autopsy, the pathologist does an external examination before the internal one. In this scene, Naomi is still fully clothed, and a pathologist would never start the autopsy by making an incision on the face.
Naomi Clark is pronounced dead at 5:33 and the coroner starts the autopsy at 8:36, which is 183 minutes later. To fit the episode title of "177 Minutes," she would have to be pronounced dead at 5:36 and the autopsy start at 8:33.
When performing CPR on a patient, the chest is always laid bare (any clothing on the upper body including a bra is cut away) to enable defibrillator paddles to be used.
It is alleged by the technical expert that on a digital data device, a pre-existing or deleted video could have been merged into a new recording unexpectedly. This is only something that can occur on analog media, such as double exposure on film, or even on VHS but usually at the beginning of the newer recording.
For a victim of a cardiac event, at no time during CPR is a defibrillator used, which is a standard practice under these conditions.