Jay was flattered by Sarah's statement that she now considered herself to be his girlfriend. They certainly had made a connection, but Jay didn't know that it was actually going this far. She made him happy, and that's something that he'd never think just a few hours earlier.
He did care about her and he wanted to protect her. But, Jay usually didn't stand up for anyone, even for himself. He could have been labeled as a wimp for that, but he usually tried to avoid those kinds of situations.
Unfortunately, he couldn't avoid this situation.
Jay stood up, meaning to defend Sarah, if he had to. But he was scared. Biff was really strong and he could beat Jay to a pulp if he wanted. And by the look in Biff's eyes, it seemed that he wanted to right now.
Biff ran towards Jay, in a typical tackle run, that he had used many times in football.
Jay cowered back into the table. He was scared.