The site pressure at a bottom of a well is irrelevant. You do realize air pressure is not what matters, but pressure as a whole? That includes water pressure.

The site pressure at a bottom of a well is irrelevant. You do realize air pressure is not what matters, but pressure as a whole? That includes water pressure. The bottom of the straw is not in a well; it’s more akin to a cassion, so you need to factor in the water pressure as well. What you’re saying would imply that the Titan submersible would be at the same pressure whether under an ocean of water, or in a well the same depth. No. The former is 375atm, the latter is a bit more than 1atm. You only need to lift the top layer of water a little bit. The rest of the water column would come up after it. Of course, you cannot lift the top of the siphon more than 10m above sea level.