[MINOR SPOILER] Can't use dockworker's shift card?

[NotAfan]

So, I stole the card from the worker that's passed out in the bar. I'm pretty sure that's meant to be used in a green door up the stairs at the docks, right?
But the door remains locked and I can no longer interact with the box thingy that's right next to it. is there somehting I'm missing?

[Du-Vu]

It won't get you in because Measurehead has it manually locked down from across the catwalk. You can use it to get back out of the harbour if you manage to sneak in, however. By jumping down from the roof of the building, which you can access through the shack behind the Whirling.