You just don't get it.
It is never safe to use unsafe signals. You don't know what will happen. You can't be sure that when things go wrong you'll get a SEGV and program death, allowing for cleanup. You don't know what will happen. Nobody knows. Nobody can predict what an unsafe signal will cause. Nobody! That's what makes them "unsafe"!
(What frame of mind is required for someone to think that it's safe to use a feature called "unsafe signals"? I can't fathom it, I just can't.)
-- Chip Salzenberg, Free-Floating Agent of Chaos