I'm guessing the real page might have more details, but I'm guessing they can at least store it for a PERIOD of time and only one, so far, is ever out and about so it can be dealt with. Euclid seems fine, or maybe to borrow a pokemon tier term, Euclid Borderline.
Addendumdum (will spellcheck this later): This was totally why I didn't do all that homework all my life. Evidence is in a shoebox at home or my teacher's desk or whatever.
So is there a limit on those time travel capabilities? I mean you could literally be protecting that thing for all eternity all to try and prevent a few bullets.
I'm guessing the keter designation is less for the gun itself but more for the possible inevitably of it being the 'root cause' of a...
Wait, if you can't interact with the shark, how do you capture it? Or is the idea that you've captured and contained the shark enough to contain it and make it safe?
"What happens next?" "transfer student shows up one day with even bigger bonkhonagahoogs. I mean humungous hungolomghnonoloughongous!"
annd yes, all that megane delinquent art at the end