to leave sb/sth in a situation that may cause them to suffer or to be treated badly ( humorous )
LEAVE SB/STH TO THE MERCY / MERCIES OF SB/STH
Meaning of LEAVE SB/STH TO THE MERCY / MERCIES OF SB/STH in English
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005