Actually, I think it probably is the point. He was asking her if she was still 'going to help me’ and (she) said 'yes,’ but Thomas didn’t believe her answer and then dropped her over the side of the bridge,” the court record states.
One suspects that the "help" in question was for her to get an abortion. He did not believe she'd follow through, so he killed her.
It's hard to avoid hoping that Mr. Thomas becomes a favorite target of the prison rape afficianados....
So he was just exercising his "right to choose".