The below code automatically secures a bag of meth.
Code:
managers.loot:secure( "meth", 600 )
Just load the above script 7-8 times and blow the lab. You will have your bags in the escape/trade (you can also use it in the escape and leave the original bags).
I would be careful about running it too many times. The trade works with 8 bags, but I suspect the game will crash if it tries to load too many cash piles (I haven't tested more than 8).