Well, anyone that works near the entrances through security will know the quickest routes.
I dont have much experience with LAX though, but from memory it is at least as large as MSP was. Which is to say, not small at all.
If they are lucky, their gate will be close to baggage claim and they can jump out for a quick one before their flight.
I'm afraid that unless you work at the airport and security sees you all the time, that the wait in line wont get any shorter.
Just tell them to make sure to talk to security nicely and return back through the entrance they exited from. It will help expedite it a little at least.