Thanks for the chapter!
Seriously though, just where are her maids and guards? Unless they're hiding I seriously doubt she'd be left unattended for so long if she's so unhealthy can barely change her own clothes. That and MC getting order wrong, should pull out uniform first and then undress her to decrease time spent with her clad only in her underwear, at least if he's going to be a gentleman. Personally I think she's either pretending to be in very poor health or at least only ill enough to call in sick but not enough to be unable to change her own clothes. My guess is really likes Souta and is either testing to see if he'll take advantage of her weakness, maintain trust by not telling anyone about her condition, and/or too shy to confess and trying to see if he likes her or develop his feelings for her.
As for the flower blooming I'm curious as to how it bloomed there, assuming someone didn't just plant it there to test the ground or raise a ruckus, and why it blooming there could endanger the school. Also, I REALLY hate mysteries where the detective solves something using information or evidence reader/viewer isn't aware of. Like in this case where president knew the girl has had fainting spells before and what caused them.