In the game of Brexit chess it’s Mays move. She’s one away from checkmate which is why she’s trying to pass it back to the EU.
Teressa May is one move away from check mate and she knows it. Her final play is to take it back to the EU to ask them for some kind of better deal / clarification / or whatever it is she thinks will help. They won’t reopen the can of negotiation worms. It’s not their problem. It’s hers, and her move, and her only move is to play for time until she is forced to make the last move of the game before checkmate. The clock is ticking. It’s game over in one.