Grace was too much focused on her clues that she missed his. By cutting the dinner short and rushing back to his apartment, he gave her a clear clue that for him she at that time was just fine one time. She could cut it off, by not going back to his apartment, or leaving as soon as he started sexual advances. If he sent her home after dinner, she might be even more upset as being rejected. Saving her the rejection was for him the justification for his urges. He brought her back home, and tried to rush so he could go to other more important things; or, a more attractive woman.
She did not mind having sex, but wished to be romanced to it. He just wanted to fool around. As it looks like she was into a guy, she missed all his clues and stayed evidently too long hopelessly waiting for him changing his focus from sex to her. The irony is that I know about a few good marriages that started as casual sex on the first date. If she was into a guy, she could play his game, and then, put the bar higher for the next date, and executing firmly being romanced into sex the next time. Still, it might not work, but we will never know.