Bad idea yes, but being kicked out of school and retorted to police isn't a proportional punishment.
The right answer would be a figurative slap on the wrist for "borrowing" chemicals from the lab, and some detention exercises to calculate the reaction results, and the pressures/temperatures generated in the containment vessel.
Yes, this. Punishment designed to correct, not a reaction based on anger.
Kids like this are not the ones you want to filter out of the system.