Those are rotating jet turbines. To my limited knowledge there's no way to just stop them. They wind down even if they had turned them off. The very first article I found searching his name showed him approach a jet that was slowly moving across the tarmac, which obviously means the turbines were turning and not going to just immediately lock up if turned off.
I don't even know that the pilots would've seen him from the footage I saw in the one article I looked at.
I don't know if this explanation will help because words. Using the photo plane as reference:
Two tools, a flat head screw driver wider than the vertical gap where the hook is, and a needle nose pliers. The screwdriver is going to be used to try to rotate the hook to the bottom left to clear the horizontal metal band, while squeezing the two bars midway to help bring the hook tip past the horizontal bar