So in the game guide it says that as soon as you enter Vault 3 that the women fiend asked you if you some questions, you can convice her with your speech or tell her you have chems, either way they wont attack on once you completed that otherwise she asks you to leave, now thats what i did, but when i can back with chems and my Great Khan simple armor and there not suppose to attack but as soon as I walk in the vault nothing happens. If i walk over to talk to her she attacks me and it becomes a frenzy and then all hell breaks loose and now all the fiends want to kill me. I did however kill all the fiends outside the vault and the fiends that are inside, but once I went to enter motor-runners room but I need a lockpick skill of 75, and well I dont have that, so my question is there any other way to enter his room besides having a the lockpick skill? i need to enter his room to complete the side quest: Aba Daba Honeymoon

Well, if you go to the living quarters section, there will be a hall filled with traps, go down this hallway carefully and you'll meet an NCR Ranger, help him with his problems and he'll give you a key to Motor Runners floor.

After negotiating your way into Vault 3 you should wait a minute for all the red ticks to go green, don't move from that spot and its usually best to leave companions outside unless your intending to wipe out the vault.
You can complete the quest now as Motor Runner will be hositle