Be touch-and-go - Idioms by The Free Dictionary
To be unstable or apt to change. Their engagement has been so touch-and-go that I'm not sure they'll ever get married. Nancy's condition has been touch-and-go since the surgery, but the doctor is optimistic that she'll make a full recovery.
be ˌtouch-and-ˈgo (whether...) (informal) be very uncertain whether something will happen or not; be risky: It was touch-and-go whether the work would be finished in time.This idiom possibly refers to a ship sailing in shallow water. The bottom of the ship might touch the sea bed for a moment but the ship still remains undamaged and able to continue moving.