Maybe you are an aircraft mechanic maybe you aren't it really doesn't matter. Though get off your high horse a gas turbine engine is no more complex than an IC engine and you show your ignorance in saying so. I am actually an engineer by trade and am intimately aware how the principle and practicalities of the design of both.
It is however entirely beyond the point. It doesn't matter what procedures are in place, should be in place, are followed or are not followed under maintenance or normal operation. To assess the situation we must look at the full picture. That is to say why is the man in a position of potential risk? In this case there is no good reason for him being there what so ever. What risk you might ask; well the simple truth is someone could turn that engine on and that man would be killed. It shouldn't happen, the procedures should prevent it, theres walk arounds by hundreds of guys, sirens warnings etc etc but that doesn't mean it couldn't happen. Take the truck example I gave: the man shouldn't of been sleeping behind the wheel; the driver should of checked everything was clear before he got into the truck; The horn blast, which is loud enough to be heard over excavation and explosions, should of been loud enough to make everyone aware that 200 odd tons of dumper truck was about to move and to make sure they were clear; the smell noise and vibration of a 78litre engine reving up in a work shop should of alerted the sleeping guy that he needs to get out of there. Trust me however if you've seen the result of a man being run over by 200tons of truck you stop giving a fuck what the procedure technically is how impossible it would be for someone to be run over, how 'perfectly safe it is to have a kip in the shade of the truck, after all I haven't finished fixing it yet' and start looking at why he was there in the first place. There was no good reason for him to be sleeping behind the wheel of the truck just as there is no good reason for that man to be sleeping/chilling/whatever in that engine. You know what 99.999% of the time your right nothing is going to go wrong. You know what as well though? That 0.001% of time you're going to seriously regret it when someone gets killed. Then you have to speak to their family and explain that John isn't coming home tonight, no you can't see whats left of the body, no Ms Smith he wouldn't of felt a thing, just a terrible accident we'll make sure it never happens again we're sorry etc etc and you have to get one of the lads to hose the blood and the mess off the work shop floor afterwards. It fucking sucks. So sure theres procedures and checks, sure it seems pretty safe on the surface of it. But thats how accidents happen and why we need things like OSHA to prevent avoidable injuries and deaths in the work place