Borderlands

Second weapons vending machine in New Haven?

Does anyone one know what triggers the vending machine across from Marcus' store to open. My husband told me about it during a single-player session so we thought it was just for going solo, but it's appeared twice now in split-screen and we don't know how. Is it console time based or something? Maybe upon completing missions for Helena? It seems pretty random, but maybe we just haven't been paying attention.

Once you complete all of Marcus' quests in New Haven the second machine will start to open up randomly.

No one's been able to figure out a reliable trigger for it. Seems to be completely random.

Supposedly if you teleport to the Middle of Nowhere and back it always opens.