Or put your any limb outside the car window. You go look up the x-ray photos on google.
Tools and knives:
Pass tools (knives, guns, nail guns, etc.) to others business end downwards and away from them (and you).
People make more mistakes when they get tired, in a routine and zone out, or simply don't Awake, Stop, Context Switch, Observe, Assess, Prepare, Operate, Breaks, Leave the area safe for the next person. (ASCOAP OCS?)