Leave somebody/something to the mercy/mercies of somebody/something - Idioms by The Free Dictionary
leave somebody/something to the mercy/mercies of somebody/something
leave (someone) to the mercy/mercies of (someone or something)
To allow someone to face the punishment or rebukes of something or someone who will not show them any mercy, kindness, or sympathy. I thought it would be best if I spoke to her, rather than leaving her to the mercy of the principal.
leave somebody/something to the mercy/mercies of somebody/something leave somebody/something in a situation that may cause them to suffer or to be treated badly: The soldiers had no choice but to run across open fields, which left them to the mercy of enemy gunners.