Mclean's a little intimidated by Riley at first. After all, she's Dave's best friend and seems unnaturally possessive and protective of him. Will she be mad if he starts hanging out with another girl? But soon she finds that Riley is always like that with her friends—she just wants to take care of people. So when Mclean gets hurt, Riley jumps in and goes to the school nurse with her even though they're not that close yet:
I stood up, picking up my bag. "Thanks for coming with me," I told Riley. "I appreciate it."
"I'll stay until you're done," she said.
"You don't have to."
She settled back in her chair, pulling out her phone from her pocket. "I know." (8.61-64)
In the end, Riley proves to be a true friend who will stand by Mclean and Dave no matter what. It kind of blows Mclean's mind, but it's just the blast she needs to understand that there are people who want to be her friends whether she's about to move again or not.