Remember, I am assuming a condition where Wing is closing fast on Lead where whichever direction the break occured, it would be close aboard, not at a safe distance. A head-to-head collision would have resulted in too much damage for either bird to make it back. This was a bumping. Anything head on would have fireballed one or both aircraft.
OK, I'm picturing Lead flying straight and level, and Wing to his Starbord, and rolled 90 degrees left. I'm picturing Lead slightly behind Wing and decelerating. I'm picturing Wing's Starbord Vertical Stabalizer touching Lead's Starbord wingtip. The only way I can picture Lead's Starbord wingtip touching Wing's Starbord vertical stab is to have the trailing edge of Lead's wing strike the leading edge of Wing's starbord vertical stab, and nothing else.
Now I'm trying to picture what happens to Wing's aircraft in the next milisecond. Rolled 90 degrees left, his aircraft turns into Lead, and somebody's radome is going to need a new paint job.
OK, now picture this: The original story never said that the accident occured during formation flight. It occured while the two aircraft were performing "daytime fighter maneuvers" which means two guys having fun on a nice clear day. When two aircraft perform dogfight training, one will break formation and the fight starts with the two aircraft closing on each other (Tally ho!) Now, these two gentlemen are head to head, and each one is going to make sure that the other one breaks first. Wing ends up crossing to the left and just below Lead, but misjudges his altitude slightly and his starbord vertical stab strikes Lead's right wingtip. The impact is severe enough that it shears off the Vertical Stab, and damages the wingtip.
I guess we'll have to wait for the official accident report.