So it basically stated that you cannot commit sucide in Kumon-me. And maybe you also cannot get killed.
I want to agrue about the connection between "bluejay" and "all is bright" / "twisting ivi". In bluejay Makoto jumped and then reset/teleported to safe place before she fell. Preventing lethal injuries is the exact opposite of surviving lethal poisoning/injures. So "all is bright" is more like "Wakana could finnaly overdose herself becose this time it is not enough to kill her", than "miracly survive after lethal poisoning". And "twisting ivi" doesn't have even this sort of connection, because there is no room for supernatural prevention of earlier attempts.
You should also remember dosens of murdered janitors. Poor guys either didn't have plot armor or it is just possible to kill somebody (maybe except suicide by friend)
And even apart from the above, there is no known rules for supernatural powers, especialy Ami's cute girl magic, so she can just ignore any restriction unless proven otherwise