Leaving the patient unattended by the anesthesia provider is unacceptable practice, period. Obviously the chances of something happening are pretty remote. And BTW, this would never make it to a jury trial. The deposition would go something like this:
"Well doctor, tell me, where were you when the patient had their air embolism and arrested?"
"Well, I was in the can - I'm sure it was only a minute or so"
"So, you actually left the OR, leaving the patient without an anesthesia provider watching and monitoring the patient? Are you sure it was just a minute? Could it have been two?"
"I'm sure it couldn't have been more than two, three at the most"
"And doctor, did you immediately return to the patient when you came back to the OR, or did you perhaps chat with the nurses across the room first, since you assumed the patient was still doing fine? And how long before you actually attended to the patient did you realize something was seriously amiss? Do you think our expert witness, the chairman of the anesthesia department from the Hopkins/Harvard/Mayo/Emory group might disagree with you?"
Defense lawyer to plaintiff's lawyer - "Do you think we can settle this for anything less than 7 figures if we keep the settlement sealed?"
I know it's unlikely. But really, you have absolutely no recourse if something happens while you're out of the room. None at all, except writing the big check. This would probably be an "agree to disagree" topic, but I can tell you, anyone in my department would be fired on the spot if this happened.
