The third and fourth pictures show the prone position cover stowed forward against the forward bulkhead. The cover would normally be down to protect the sighting head and provide a smooth working platform to get at the kit under the pilots' seats. Also for access the radar forward of the bulk head. The first image shows the access to the radome.
In that last picture, on the right is a brown cable which protects the bomb firing button. The button grip is the grey corroded shape to the right. The red safety flap would because locked when a nuclear weapon was loaded.