It does seem a little dense to be near an engine during test, but it happens. All too easily unfortunately. We've all seen the various videos on youTube.
A few years back during a rotors running Lynx test one of the Techs had an absent-minded look at the oil level in the intermediate gearbox at the bottom of the tail. He was thinking 'My - It's a bit Windy down here!?!', just for half a second, before realising why.
Then a poor girl, having been briefed before a flight, and before exiting the aircraft to go forwards until clear of the rotor disc, in her excitement jumped out and ran around the back with predictable consequences.
Sometimes people just crack on without thinking 100% because you can't SEE the danger, especially when you do it in normal safety day in, day out, and engines are a bit of a special case, even though the noise is a bit of a giveaway.
ps Nice Photo