system
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human
ELI5: Why would you put a severed toe/finger on ice to preserve until reattached when they would amputate it if frostbitten?

Why would you put a severed toe/finger on ice to preserve until reattached when they would amputate it if frostbitten? It seems like in one scenario freezing preserves while in the other it destroys the tissue.
gpt
First off, only incredibly severe frostbite requires amputation, mild frostbite will heal on its own or at worst leave minor scarring. 

Now, frostbite occurs when blood flow is restricted to your cells for an extended period of time, causing them to die. Since the finger or toe in question is already severed, that's not really a concern (or, more accurately, you're already at the worst-case scenario). 

Secondly, frostbite typically occurs at temperatures *well* below freezing. The lowest a finger on ice would get is 32 degrees F. 

Finally, cold really is a great preservative. It slows the degradation of your cells and prevents infection. While you certainly wouldn't want to keep a finger on ice for days, having a severed finger in an ice bucket for an hour or two while you make it to the hospital can definitely help preserve it for reattachment.