Okay, so you let’s say you DON’T mirandize the kid.
And you ask him, and he mumbles something about a storage locker. You send other officers and EOD to open the locker. There are no devices in there, but there are a whole lot of written notebooks detailing the planning for the crime, naming other accomplices to the crime, and a whole bunch of stuff - a veritable gold mine for the prosecuting attorneys.
Except later, the defense moves to exclude all of that — it turns out what the perp claims he mumbles to you was “there are no bombs in the locker but my notebooks are in a locker at...” Some leftwing nutbag Obama-appointed judge denies your public safety exception.
So all that stuff is excluded. And now the best the prosecutors can argue is that investigators had an independent source of that evidence - they would have found it anyway. Is that gonna fly? Maybe, maybe not.
As I say, this college kid ALREADY KNOWS he doesn’t have to talk to police. He’s seen a thousand cop shows in his life. You gain nothing by not mirandizing him.
I agree he probably already knows he doesn't have to say anything, but I've been surprised how many people will still talk to me, especially when they're lying on a stretcher with severe injuries.
If they do administer Miranda, and he agrees to talk, they can't question him at all and get anything useful, because of his condition.
At least under the public safety exception, there is a chance at discovering new evidence. I think you bring up important arguments, and I don't think you are wrong. A liberal judge may indeed throw it all out. None of it would ever even make it into the courtroom if they Mirandize him, though.