Nearly died twice in two days at the hands of the same student, whom I shall call X.
The first time was Thursday. It was myself and a student flying fingertip exercises on the wing of X and another instructor. We were in a 1.5G gentle, climbing right bank turn and in position, (so slightly higher and in the same plane of motion)when without any warning he bunted his nose down (putting us high and quickly trending towards blind) and rolled quickly towards us. In a fraction of a second we went from being safely in position to rapidly close to death. I knew without thinking that there was no way the instructor in the other airplane could do anything because I could see his hands above the canopy rail, away from the controls. Without hesitation I immediately took the aircraft from my student, rolled left, and pulled for all I was worth. Time slows down in moments of terror as the 'fight or flight' response kicks in. I distinctly remember closing my eyes half way as I waited for the impact, holding my breath and flexing as I was pulling all 5G's the mighty Texan 2 can pull at whatever airspeed we were at. As the moment I felt we would have died passed I eased up on the G's and called "bandit 2 breaking out" per the standards; much relieved I was still there to make the call. The Instructor Pilot in the other aircraft later told me that we came within 2 feet of colliding, and that he too closed his eyes for impact as his canopy filled completely with the dark blue shadow of the belly of my Texan about to crush his skull. Only after he heard the stereotypical world war two fighter sound of a dive bomber peeling away did he open his and utter 'dear Jesus'.
When flying in formation you never should hear the other airplane really... we're in a pressurized canopy, wearing ear plugs and bose quality sound canceling integrated helmet-headphone-mic. You can barely hear your own engine. In the T-38 you only heard the other airplane if it was pitching out and pointing it's twin jet engine exhausts at your cockpit, and that thing is about 3 times as loud as a T-6. So the fact that he heard us just adds to the fact that we were seriously about to crash.
I'm the scheduler for our flight, so it's my decision who instructs whom. I've got a lot of power and control over the training of students and the lives of my fellow instructors. After that ride on Thursday I decided that the only safe solution was to have me in the cockpit of student X. Friday I flew with X.
I have taught a lot of kids how to fly formation. I've successfully instructed international students from Afghanistan and Bangladesh. And up until now those were the most challenging students I've ever worked with. Until student X.
I shit you not, he cannot move his left hand and right hand independently. I know he can or he wouldn't have continued this far in the program. I think he's afraid of the other airplane, or terrified of doing something wrong- thus leaving him either not doing something when he should, or completely over-controlling the aircraft. I made some progress on Friday, but I've never had to work so hard to keep someone from aggressively swapping paint with his classmate. I can't think of an equivalent in the civilian world to what it was like. By this flight he should be able to fly in fingertip (10 foot spacing) doing lazy 8's at 90 degrees of bank at least safely, where he recognizes unsafe closure. no one is expected to do it perfectly yet, but he's only 6 flights away from solo-ing. We spent Friday doing level 30 degree bank turns and it was still life-threatening.
We're flying on Sunday to try to catch up on the time line. This class is supposed to track select on the 28th of September and we're 10 days behind the time-line. I cannot afford to waste instructor availability, but as scheduler I've decided to fly student X only against two other instructors and not against other students for the next two formation rides. At least that will be the safest situation I can possibly make, and the training of all the other studs won't suffer.
I'll post next when he flies formation solo or is kicked out of pilot training for inability to fly formation.

The nice thing about helmets is it hides the horror on our faces.