A kid is taken hostage momentarily, but is okay. It is implied some kids may of died on the other side of Starlight Beacon, but it is no seen or discussed.
There is what is basically a therapy scene, with a character on extended leave with a coach on an island to deal with his issues, but it’s nothing like institutions as we know them.
The hijackers are clearly on a suicide mission when they plan to destroy Starlight Beacon. Another character at the end of the book sacrifices himself, which this character had been struggling with severe depression.