It seems that Haruto was also a movie fan as well as a basketball fan and was such a fan of Jake because he saw that he was also a good actor, was the first person Jake knew that was really his fan and became his friend for it.
Jake had a good memory and so still managed to talk about the talk with Haruto and the two did well in the report at the end of the talk unlike the other two who didn't even pay attention to the talk.
So Jake and Haruto became friends because Haruto was a fan of Jake and because Jake wanted to hire Haruto to work with him in the future, after returning from the lectures Jake returned to his dorm to rest.
After a week since the Boston Marathon Jake could finally return to training, he himself felt that after resting for almost 3 weeks between these marathons he was much more rested.