Dangerous situation. You have accidentally or on purpose ended up in disastrous circumstances. It does not necessarily intend that a situation is fatal, but it might be the end of one’s relationship,  job or lifestyle. (Compare to Within an inch of one’s life or Living on borrowed time.) {See 50 Levels of Anger video.}

“I told the boss I knew how much every employee was paid, but he cautioned me to keep it to myself or I would be on deadly ground.”