This is the Vault-15 entrance section of the map of the wasteland presented by:
Here is the cavern entrance. Just like at Vault-13, you should kill all of the rats and search every-where. On the first level in the medi-center there is a locker with some stim-pacs. Be sure to pick those up. To get to Level 2 you will need a rope (found in shady sands).