OP, this looks like a pretty straight forward situation to me. This has nothing to do with VSC.
It has everything to do with you still having steering lock applied when you dropped 2 off and immediately came back on track. You hooked the car. This is almost impossible to save. Think about it this way: When you drop 2 off and your steering wheel is still turned in a direction that will take you back on track, the FRONT tires gets back on pavement first and regains traction. However, the rear still doesn't have traction while it's on dirt. Then the rear suddenly gains traction as it comes back onto the pavement, and you still have steering lock. What happens then is major oversteer. The vast majority of cars have been lost on the race track in this fashion. Turn 3 and 4 at Laguna Seca. Turn 15 at Thunderhill.
What you should have done:
a) Realized that you were going too fast through that turn and that you weren't going to make it
b) drive straight off the track. Not just off. Straight off.
c) allow the car to settle and slow down off the track
d) slowly and gently bring the car back onto the track in a fashion where you are gliding back onto to the track with your steering wheel pointed straight forward as you get back on.
All this other talk about countersteer, adding throttle, reacting faster, etc, etc means nothing. As soon as you dropped 2 off, that all went out the window.
BTW, this wasn't a tank slapper. A tank slapper involves the rear end rotating from one direction to another. You only rotated in one direction: counter clockwise.
Glad to see that all you needed was a vacuum cleaner to get back into play.
