
That last frame in chapter 25 reminds me of this
http://www.mangago.zone/read-manga/saezuru_tori_wa_habatakanai/mf/manga/saezuru_tori_wa_habatakanai/c001.1/pg-41/

I agree. It's because those two times were the only times Yashiro's shown any true emotion since he was a little kid. With all of the abuse he's had done to him and the abuse he's put himself through (more than likely because of self-hatred, I'm sure he blamed himself to some extent for not fighting back or for having a physical reaction), he's been locked inside a shell for decades. I believe he's been afraid to truly care about someone else for fear they would reject him in disgust of what he assumes is his true nature. He uses that so-called "true nature" like a blade holding people at bay. That shell didn't just crack with the experience Yashiro just shared with Doumeki, it completely shattered. Caring about Doumeki snuck up on Yashiro, because he always considered him safe since Doumeki was impotent. I think he just realized how much Doumeki truly cares about him, and just how much he actually cares about Doumeki. It's got him completely spooked, and he doesn't know how to deal with it. On top of that, this was the first time Yashiro has ever had sex with someone he was genuinely attracted to. I'm sure he's scared to death and doesn't know how to handle the emotions right now.

Why does it feel like him interfering with the past is what actually may have caused the accident. Hope I'm wrong.

exactly what i thought.. it's like a consequence for trying to affect the past.. it feels like that to me.. so a sad and painful end is what i foresee.. i hope we're wrong abput this coz it's gonna break my heart..
Pulling at my heart, one painful string at a time.