Sheppey.
We had things like that once in a while, however planes like a 747 are not really supposed to fly the whole envelope at N-4.... If I remember correctly, the windmilling engines would not generate enough hydraulic power during speeds below 250 kts after extending flaps (electrically), so one could or would run out of control.
As an APU was not always available to get the hydraulics going.
The one time I did it, the SIM lost it shortly before "landing". Programming was just not sufficient in that region.
One can exaggerate SIM training into scenarios that are so remote, that one could end up in "negative" training, so it would backfire and scare people into psychological problems. Nobody wants a result like that. Training is a delicate business, not as easy as some think. Parallel to increasing skills, self confidence should grow in harmony. But the last one can easily be damaged trying to max out the first one.
That is the reason why SIM instructors have their hands at "freeze" button, when things are likely to run into a crash scenario. I have never witnessed it, but those who did say the last seconds were horrendous realistic.
In my GA flying I once got a student whose previous instructor had him drop into a spin with a Cub, during training stalls. Not briefed before, not warned, nothing.
He learned to fly in the end but never really got rid of that anxiety.