I listed for a jumpseat SEA - CVG on the 22nd. When I asked for an address, I was given 2. One was the pax terminal at SEA and the other was a mx operation at BFI 🤔
The door will be locked when you get there. Sometimes, you'll catch one of the rollup doors open and can sneak in that way, but not usually. Knock on the window that is three or four windows to the left of the door and somebody should show up to let you in.