I suggest that the Captain's tone may have been due to his/her wearing of an oxygen mask. In any pressurisation incident, the flight crew would go onto oxygen as a sensible precaution if nothing else.
It is quite rare to lose all pressurisation in an aircraft, it may possibly have been due to loss of control of the outflow valve. Such incidents have happened in the past because mobile phones on board have interfered with the valve controllers. Like many other systems in the aircraft, they contain sophisticated electronics which are intolerant to the sometimes powerful emissions from mobiles, especially in the acquisition phase.
Such a cause would not surprise me, it's amazing how many passengers still refuse to turn them off!!
