Those talking of parachutes, the KC-135 and E-6 (the military 707) both have blast doors to enable parachute egress, though the 135 crews have had their parachutes taken away as a cost saving measure.
A little difficult to see how a similar arrangement may be incorporated for crews on the upper deck of a 74, outside of a scramble down the stairs to access a hatch on the lower deck.
Air Force pulls parachutes from KC-135s