There is some sort of bunker thing right outside of tenpenny tower and it goes down, i got in there once before but i couldnt get that far. there was glass or something seperating me from the rest, it looked like the entrance to a vault. if anyone knows of a way to get in there let me know.

Erhm, do you mean the metro system right outside the tower or the maintenance entrance which is literally right by the tower (and inside the walls).

Regardless, there's a metro system underneath the tower that is part of a quest (no vault). Talk with Chief Gustavo. The entrance however, is in a little trainyard to the right of the tower (as you exit it). Its past the intact house.

You mean right behind the tower? That's the access tunnel for the hotel's access to the Metro Tunnels, it was built before the Bomb to ensure hotel patrons could reach the tunnels and get to safety.

You can get here during the quest named 'Tenpenny Tower' by talking to Chief Gustavo and choosing to help Roy Phillips and the Ghouls take over.

I hope this helps.

Edit: Damned Enclave stealth units.

Always a step ahead. Colonel, always a step ahead.

*puff of smoke*