I played through Dead Money twice. I was friendly to her the first time, and allowed her to access the computer without going down the elevator to open the casino. She was friendly when I met her in the suites. I sent her down the elevator the second time, and she became hostile in the suites.
I think there is two points for Christine one is as mentioned in the quote above, the second is trying to convince her to let YOU handle Elijah. There were at least one speech check if i remember during the final conversation in the suites before she opens the elevator. I could be wrong about the suites because as i loved her character especially the sad lonely ending SHE chose for herself, i really made sure i did not piss her off during the final conversation. I am not sure about the second but yes if you send her down the elevator she will be pissed when you let her out.
Asai