You would be surprised how numb you can get when working around running engines. I was in the hydraulic hell hole on a DC-4 adjusting autopilot hydraulic pressure which required the engine be run. After a half hour in there, no ear protection in those days, amidst a lot of whining and screeching noises from the hydraulics and the engine noise, I backed out the hatch which was just fwd of the wing L/E on the right side. Engine of course was right there, even at idle making a great deal of noise. I turned right, took a step and realized there was a prop whiling a foot in front of me. Another step and I would have been into it. Stupid of me of course, a lesson I learned at no cost fortunately but my knees still get that weak tingle whenever I think about it.