"Mullroy: Not breathing.
Jack Sparrow: Move.
[Jack slits the ties on Elizabeth's corset and rips it off, causing Elizabeth to regain consciousness, and spit out a lot of water]
Mullroy: Never would have though of that.
Jack Sparrow: Clearly you've never been to Singapore."
I think the inference is that in Singapore nobody would think twice about ripping open a woman's bodice!