Editor
Place "Hunter" first and other 3 rifleman in the same squad, specify "In Cargo"
Fire up the game
Get out of the vehicle, you already have your weapon ready
Order AI out of the vehicle, they will get out with the weapon on their back, then make a painfully slow animation to retrieve it while standing still, or run 2m or do the same.
Order them to get in and then out again and their weapon are ready.

Works the same in a danger situation, just try to be a 50. cal sniper and shoot the engine, they'll get out in the same fashion.