There is no "cockpit window" option on the jumbo. There is a hatch at the rear of the flight deck roof and 4 single use inertia reel devices to let you down gently as you leap off the roof of the upper deck. Down the stairs and through the main deck doors is the only option.

The upper deck doors are the flight crew's primary escape route and the hatch will only be used in extremis, if the door is jammed for instance.