Hi DozyWannabe,
One would hope that the fact that the Stall Warning was blaring as he made his way to the door and continued to do so for 2 seconds after he entered would have been a clue.
Do you mean - a clue that the Captain thought they were no longer stalled?
In Normal Law one should never hear the stall or overspeed warning.
In Normal Law & with the AP engaged, if you are higher than ideal profile, and select Managed Descent from FL390, it's easily possible to trigger the O'Speed Warning.