Underground Areas

[The Krusty Bunker]

Does anyone know what zone the 4 underground areas are in? I would like to do practice runs on them before I spend an entire evening trying to finish the Lair Slayer achievement. I know the 1st is in zone three, but the rest?

[Mozthic]

There is one in each of the 4 zones

[bobbyhopadop]

anyone who wants to go for the lair slayer ach message bobbyhopadop on live