You forgot to add that Christian told her in the morning if she is not there the dinner is off.
Precisely. All else taken off the table, she (at this point) thought Christian was testing her by telling Hutch to leave her behind. She had been told it was off unless she was there, so she had no choice but to go or, in her mind, Hutch would be out of a job. So it was a test to see if she
could overcome this, and if she
would overcome it, to go regardless.
I thought that was one of the really neat parts of the game actually, coupled with the "oh shit" realisation that it was actually a test of Hutch, not of her.