I think he means the one where the "Environmental Engineering Personnel Only" ladder runs down. Unfortunately due to the protective grill there a few clear shots of this.
As you've mentioned Charlie X
, here's a question which has bouncing around my mind for while - WHAT on earth are those guys doing in that scene? The glowing light seems to suggest a power reactor of some sort, should it really be that easy to open up a cover to the atomic piles?
The pole appears 12' long at least, why is it even on the ship? What does it do?
And so on. Anyone have any thoughts?