I always think it's weird on cop shows and the like where an assaulter is in custody, the victim is in the hospital, and someone says "If he dies, you're in big trouble!". The criminal has already done whatever he did, and now somehow the severity of that doing rests with the competence of doctors.
It makes sense as an interrogation tactic, at any rate. If you're going for a confession and the person is distraught (either by what they did or by getting caught doing what they did) then it's a variation on "confess now or you'll get a worse sentence" with the added bonus that the timeline on the "confess" is both out of the interrogator's hands and it doesn't seem artifiical to the suspect.
Here's the new thread for posting quotes, with the usual rules: