Well, if you are a part of the accident, don't let the LEOs take custody of your firearm. There's a thread around here somewhere where that happened. The owner had to go to the hospital and gave his firearm to the LEOs that responded.
They are taking the opportunity to go over his firearm witha fine tooth comb to ensure it's fully legal and legit, never been used in a crime, etc... all without RAS.
I would think that it'd be better to give your firearm to a trusted 3rd party (like friend, relative, spouse, legal age children, etc) instead of to LEOs. Either that or keep it on you.
Responding as a good samaritan, it would probably be a good idea to secure the weapon so it cannot go bouncing around or whatnot if the carrier is unconscious / unresponsive. Beyond that, I wouldn't do anything special.
A lot of the rules the military SOPs have are often based on good ideas / common sense / things that work. They would make for a good starting point.