Unless you consider this, which I posited earlier and could fully see based upon the descriptions of those who know him (even here) and the fact that he was a volunteer coach for a local Christian high school: He is a big goofy teddy bear who has a heart of gold and sees 1) Hannah stumbling/confused, 2) WG following her and ducking in an alcove, 3) flock of "frat boys" harassing her - we have no idea what those boys were saying/doing, but they could well have frightened her, causing her to increase her speed. He catches up to her, puts his arm around her and says, "It's ok, I'm going to get you away from these guys. Walk with me [here] and pretend you know me and we'll call someone," fully willing to accept the potential subsequent punch to his face he might get - because that would at least get Hannah help. He takes her to Tempo. He buys her a soda. She texts a friend and says, "Thanks. I'm good now," and he or they leave.
Did she get in his car? Only JM seems to know that for certain, potentially LE now with the warrant to search his car and subsequently his apartment. Perhaps she did. Perhaps he drove her back to her neighborhood. Perhaps something else happened there, right where the other two assaults happened, each within 24 hours of this and each other.
LE needs JM. One way or the other.