So I go into LVB Station and engage a long conversation with a trooper. To this point I've never done a bad thing to the NCR and I've actually helped them on a few quests so we are all freindly. Anyway, I go upstairs and the guards open fire on me! Veronica really doesn't like this bs so she kills them as expected. Funny thing is, I'm expecting everyone in the place to now be hostile but the trooper I talked to is still talking to me as well as the other troopers on the first floor.

Anyone know if this is a bug?

Usually if there are two guys standing on opposite sides of a door, it is unwise to walk past them.

Okay, but now they are on opposite sides dead. Lot of good it did them for getting all pissy over me opening the door. How do I take the tram if I don't go through the door?

You must be at least "Liked" with the NCR or wearing NCR armor to be able to use the monorail. Any lower and those guards at the gate will attack you after they give the warning not to come near them.