The act of knowing that something terrible is going to happen, but hoping that it will resolve itself without any further intervention if you wait long enough.
"I accidentally prescribed that patient the wrong dose."
"Are you going to warn them?"
"Let's just wait for Sue Gray."
A pathetic excuse given to defer blame from the actions of a cowardly person, usually a person of authority
“Did you here what John did the other day to try and get out of being honest about cheating on his girlfriend?”
“Yeah, apparently he did a Sue Gray”
To Sue Grey something is to attempt to delay the inevitable.
We're waiting on Sue Gray