Wow! Talk about being thrown into the fire right out the gate!
It looks as though this topic has pretty well run its course and I would echo the advise given by Pathfinder as avoiding this predicament is your best option, but I will touch upon two aspects related more to selection of a rifle for this particular situation.
First, selecting an AK for use or deployment from a vehicle. I did manage to listen to the pod cast in question, but I did not read the blog or other discussions, so please excuse me if this has already been covered. The idea of using a weapons platform that does not have a buffer tube to allow for a true folding stock is a valid concern. Even 11" AR's can be cumbersome in a confined space such as a vehicle. Note I said "cumbersome", not unmanageable. I still see images of Marines using 20" M16's in full battle gear, operating inside HUMVEE's during convoy operations. It can be done, but it does take some training and practice. A rifle with a folding stock will greatly improve confined space movement. Having said that, I would not select an AK. I say this purely for perceptional reasons. No one can deny the reliability and durability of the AK. It's biggest problem is perception. An AK is what the black hat is to an old western movie- bad guy. No matter what the situation, if you deploy an AK in any kind of public setting, you will be deemed to be a bad guy, terrorist (either foreign or domestic), or active shooter nutcase. I doubt very much that any LE would even give you the chance to demonstrate your intentions. Most LE would shoot on the sight of an AK simply because of what it represents. The second you started cranking rounds into the air to disperse the crowd, you'd have rounds in the air coming your way.
I would strongly consider some other platform that does not convey immediate bad guy status.
Second, penetration and retention issues. Proper load selection, even with an AK will help with penetration issues, but the fact remains that mobs are by their very nature defined by large masses of people in a very tight group or confined space. Any firearm is going to have penetration issues because if the bullet leaves the body, it will have an extremely high probability of hitting another person. It's an issue of odds more than overpenetration. Give the penetration concern its due diligence, but I would not let it rule my decision were I faced with a potential mob situation.
Retention concerns? I wouldn't be concerned with it. You can defeat one or two subjects trying to disarm you if your skilled at CQB retention technques, but not 5, 10, 20, or 30 etc., you get my point. If a person is close enough to you to take a rife away from you, he's close enough to get your pistol. It may require a little more skill or determination, but it can still be done. I would not shy away from a long gun in this situation. The intimidation factor alone may be enough to cause a mob to back off, but if the mob is determined, only for a short time.
Erik