After getting through the parking structure, these guards will approach the player and initiate dialogue. If the player has not yet freed Jillian from the Reservation and completed the prisoner retrieval quests, the guards will basically say to get the hell out of here. If the player is a good Charisma Boy, then he should be able to get some information out of the guards pertaining to what the Rusty Hooks are and that they are always interested in some trading as long as the trader does not care where the loot came from. If this is acceptable to the player, they will let him pass and tell him to meet Bear in the main walkway between the workshop (Rocket Assembly Building) and the homestead (Operations and Communications building). They will also insist that the player keep his weapon holstered.
Character type completion breakdown
Combat Boy - If the player has completed the prisoner retrieval quests, and the player had not killed Jillian, then the guards will let the player pass with honors. If the quest has not been completed, then the guards will tell the player to piss off. Should the player refuse, or if his speech/persuade is not adequate, the player may choose to mow the guards down. Since gunfire is loud, more Rusty Hooks will pour into the area (~10 to 15) accompanied by four NCR guys with high powered weapons and combat armor. Good luck.
Diplomacy Boy – Can talk his way into seeing Bear whether or not he completed the prisoner retrieval quests.
Science Boy – Pretty much the same as Combat Boy, except if the player is good at science and mechanics and mentions it to the guards, they will let the player pass and instruct him to meet Bear first, the Sid.
Stealth Boy – Straight forward, here. If the player is capable of sneaking passed the guards, he can meander pretty much anywhere. However, if the player fails his sneak and is seen by a Rusty Hook, then there will be hell to pay.