Cooba is your local smart(-), for your knowledge.

In any case...


After unlocking door 1, you should go back to the starting spot (1). Then you should make your way to point (2). There's a tricky sucker tube on your way though, you should approach it slowly so you can pass. Anyway, you should end up in a place with a lot of warps. Play around with them (their order doesn't matter) until you get to point (3). When there, you should go right (unless there's a door there, it's there if you didn't unlock door 1) and then door 2 should be open, and so should be the Tzar Caves door. Have fun exploring the large maze, by the way.