I would have been fine with Lilly, Hanako (? burn victim), or Emi, so I didn't really have a problem with it. I didn't have any problems with the writing, I think the mai waifu visual novel game concept is not that compelling to me in practice. Oh well, different strokes.
Oh, I got it. When I chose to "push myself" at the track, that's what led to Emi's path. I actually picked that option because I was curious to see if I could actually die in the game, but both options seemed to end with Emi inviting me to lunch on the roof so I just went with pushing myself. Should have realized that sooner.