Back to the present, she sighed deeply. 'What use is there thinking of that stuff now? Ru is no longer here; he left me alone in this cruel world.'
Right before she could tell him the words he said to her that day, he left her. A part of her most likely holds a grudge against him for being so selfish. According to Shin, Ru already knew people would chase him. But he still accepted her selfish wish of going to the concert together.
There was no particular reason why she wanted to attend together. But recently, she found his behavior weird; she felt that if they didn't go together, she would no longer be able to see him. The phone call they had on the morning of her concert made her feel strange.
It was because of that odd feeling that
'There is also evidence that says Tsueno Mamoru is alive.'