Personally, I always thought the cockpit was a module that could be 'ejected' as an over-sized escape pod, though compared to the one C3PO & R2 rode down to Tat, about the same size... he-he, wringing my hands....
R/ Robert
Yanno.... I thought the same thing. I mean perhaps that's why the ribbed ring around the outside of the cockpit corridor is there. I often thought that maybe if the ship ever takes a major hit in the main saucer section, the chances that the cockpit would survive is much better and can be detached from the main ship as kind of a hidden escape pod! Would make perfect sense to me!