May be I've not clearly understood your first message or may be you haven't understood my answer.
Please apologize, as english is not my native language
I've never said that elevators doors were watertight, they are not at all.
I've just said that the elevators doors are located at the same frame number (43) than one of the W.T.D. starting from F Deck.
So, that elevator doors and that W.T.D. were located on the ship in a same vertical plan.
Regarding elevators doors and as usual :
At each Deck deserved by the elevator you have a wrought iron sliding doors avoiding people fo fall in the shaft when the elevator is not at that floor and one another sliding door on the mobile part of the elevator as clearly shown on the draving I've posted here above.