leave flat

[leave flat] {v. phr.}, {informal} To quit or leave suddenlywithout warning when wanted or needed; desert; forsake; abandon.

Sam found that being a member of the trail-clearing group was a lotof hard work, so he left them flat.

My car ran out of gas and leftme flat, ten miles from town.

Compare: LEAVE IN THE LURCH, WALKOUT(2).