Do we know that anyone *tried* to unlock the door after the initial 5 minutes?
If things were getting as hectic as we've heard, I can imagine them stopping trying that and just trying to beat the door down. It *could be* that the door would have unlocked if only they'd tried the code towards the end.
Can this be verified audibly on the CVR, one way or another ?
And if one puts in the wrong code what happens ? Does the door seal itself for 5 mins, or can you try again immediately ?