save one's hide
save one's neck

"It proved extremely difficult to put an admirable (much less heroic) spin on burrowing into the earth to save one's hide," he wrote.

Following the first principle of saving one's neck, we'd chucked it.

So does imminent retirement, with a difference: the issue is not saving one's neck but living out one's days in reasonable comfort after the weekly paycheck is gone.

Any dead body found in the cell and accepted as the prisoner's would of course be carried out and guillotined-suicide does not save one's neck from that fate, once the People have commanded it.