Totally surprised on entering the mist.
Good post Walter.
What you describe is far more likely than a deliberate, controlled, headlong rush into IMC.
The crew flew much closer to the fogbank than they intended. That could be caused by TANS mishandling or malfunction followed by Visual Illusion.
And that Caz and JP is Aircrew Error, not Negligence.
I advance this theory as a possibility. Like everyone on this thread, I cannot possibly know what happened.