The injector is made out of steel. Not sure of its Rockwell hardness, but pretty sure you would have to put some 'umph' into your drilling to go through it. Even if you hit the injector, there's a tiny amount of fuel in it, and even if the fuel could "flow" through it just sitting there, not sure there's enough in the line to somehow weep downwardly, although gravity would certainly move whatever fuel from high to low. Take a paper towel to sop up the fluid and then do a smell test. I agree a little bit of diesel or other similar fluids can stink up the garage where everything stinks like diesel, especially once it gets atomized and in the air.