Following the required speeds and flightpaths, it's basically certain you will end up straying from the MOA and failing the mission just before or during the spiral dive. Interestingly enough, the better the flying preceding the spiral dive the more probable you are to exit the MOA.
Watching Recon Sterwart's video, he also comes dangerously close to the river (20:48, TAD), and doesn't fail only because previously during the spin-stall he deviates quite a bit (17:25, pointing 320), and then turns towards the WP rather than the briefed heading (17:55, pointing 065). He also starts climbing way before the instructor's VO (18:35, at 12700 feet already) and at a too high angle than what is published as correct procedure (>160 knots, should be around 180 knots at that altitude).
The underlying problem I think with this mission has always been the fact that one has to repeat it multiple times not for the difficulty of the manuevers involved, but rather to learn all the triggers and anticipate them. I went in after one year of having originally passed it, and although I flew it perfectly (and because of it) I failed it due to me not remembering the MOA limits (the briefing may be lacking a map), and that I shouldn't listen to the IP under certain circumstances.
Simple fix: remove the MOA limits. It makes no sense for those to be there in this mission, since the pilot is supposed to be following the IP's instructions regarding navigation. If I follow them and I end up exiting the area, it shouldn't be my fault shouldn't it? Not in a setting where I can't provide direct feedback on the situation at least. :D