No lifeguard is on duty: swim 'at your own peril'. [='at your own risk']
The species is 'in peril' [=(more commonly) 'in danger'] of dying out.
Restaurants that ignore the smoking ban do so 'at their peril'.
(..) Kowalski. We'll need to win the hearts and the minds of the natives. Rico. We'll need special tactical equipment. We're going to face extreme peril. Private probably won't survive. Alex! Come out, Alex! The boat's here! We can go home! Alex! Alex! Alex! Alex! Alex! Alex! Alex! Alex! (..)2005 Madagascar