Shawbury, early 90s. I'm about to embark on a low level navex with my stude, who had arranged for his parents and girlfriend to be at one of his turning points. We brief and clamber into the mighty Wessex. Bloggs is doing really well as we approach the appointed TP. Spies his nearest and dearest, briefs next leg and then gets a bit of target fixation. He fails to spot the 250' wires just beyond the TP and I let him plough on until avoiding action is required. I take control, rack on 60 deg AOB and retrace our steps. Bloggs is somewhat confused until we turn back onto track and he sees the wires. Blood drains from his face and I give him control once more. Sortie concludes, I debrief him without even mentioning the incident, give him a B for a very good navex and we part.
Fast forward 15 years and I am squadron duty auth at a secret Hampshire SH base when the phone rings. I announce myself to unknown caller. Caller is silent for a moment and then asks "Not Flt Lt Kintyred who instructed at Shawbury 15 years ago?" I confirm that I am the same and he says, "It's Flt Lt Bloggs.....and I still have nightmares about wires."
PS. A well-deserved MiD must go to my very brave crewman who, trusting that I was going to use the situation to make a point, didn't alert Bloggs to our impending demise.