Talk:Miyuki Koshiki/@comment-112.211.186.169-20141102123201/@comment-25715061-20161007131940

Judging by the visual novel, there were two real timelines, second being created by Riki by sending a message to his past self. That way he became somewhat different in that second timeline(which is shown at the end of Refrain and in which the true ending of Kurugaya's route takes place), so it's possible that he could persuade Kengo into going to the rooftop with them and, as a consequence, save Miyuki.

So, she's deceased only in the first timeline. In the second, presuming her alive makes the most sense.