HOLY COW!! That's what happens when you give a lazy/ under-qualified mechanic an air gun. I would definitely have a talk with your mechanic and let them know if something like that happens again you, and your business, will be going else-where. I usually don't use a torque wrench when putting my lug nuts on (I just crank them down), but I sure don't tighten them down so much that I can't get them off again. Just make sure that they lower the air pressure in the gun before they put your wheels back on.....because they should take them off and put them back on for you free of charge.