How to get there? (Borderlands: The Pre-Sequel)

Quest: Home Delivery
Gives out: Hammerlock
Location: Concordia (sort of)

During the quest, that zone will be visited. Now it is blocked by textures. I don't remember when the quest will be available. I've only done it a couple of times.

seroz
As far as I remember, the passage opens when Seymour's task is to get 2 frozen threshers.
Spoiler

Thank you - I'll look ... I'm
going through the second "layer", almost everything went through, but I didn't get the right one, there are 5 unsolved tasks left - maybe among them ...