Perhaps there are two different issues being discussed here.
One is a condition where the engine has either flamed out or been shutdown at altitude and is being restarted by SOP.
The other (which I spoke about) is where the engine EGT goes up into the red while the N2 fails to acclerate at all.
The later case is indicative of a engine hung in a stall condition.
At any rate remember if you allow the N2/N3 to get too low for any reason then an air start is not possible without assistance. In an all engine out the roll off of N2/N3 below starting conditions is most often associated with the pilots desire to configure for maximum glide Lots of things on your mind when you are a glider.