In fact, one of the two things that makes Kuwana angry and emotional for real is mentioning her death and how he was responsible.
Yagami continuously brings her death up in arguments with Kuwana later on and uses it as the main justification to put him to task for his murderous Bully Hunter crusade. I Let Gwen Stacy Die: Her death is primarily used to make Yagamis quest far more personal and give both him and Kuwana angst.Hot Teacher: Young, easy on the eyes, and has a soothing, deep voice.Sawa: Everyone keeps saying "Ehara's son" like he's just another statistic! He had a name, for heaven's sake-Toshiro! He Had a Name: Invokes this in regards to Ehara's son, who she knew personally.The first being forced to tell lies about the whole Mikoshiba bullying incident, due to the pressure from the school, and indirectly the law system itself, and the second being with getting threatened by Mamiya and indirectly, Kuwana at Plage to not talk to Yagami about his case, although, luckily, she opens up to him either way. Both were/are teachers, but whilist Kuwana, or, as he was known back then as Kitakata, took a blind eye towards his class and the bullying going on inside it, Sawa immediately wanted to take action once she saw the bullying that was occurring in it, and generally cared for her class and her students quite a lot. And considering the horrific extent of the bullying that Mitsuru went through, who can blame her? In the former's case, she was so sickened by the Lack of Empathy from her former peers that she'd rather visit Mitsuru in his comatose state than attend a high school reunion. Everyone Has Standards: Naturally, she's none too pleased with the bullying that led both Mitsuru and Toshiro to commit suicide.Enthusiastic Newbie Teacher: Being in her early 30s, she's considerably younger than the other teachers seen in Seiryo's faculty office.Dying Clue: It's implied she used her blood to help Yagami find her school yearbook, which would prove crucial in identifying her connection to Kuwana.
Kaito makes sure to close them out of respect. Dies Wide Open: She's found dead with her eyes open.During Chapter 4 however, she becomes a bit more trusting towards him.