burn your boats
burn (one's) boats
To do something that cannot be easily undone or reversed in the future. Primarily heard in UK, Australia. I think you burned your boats when you announced you were quitting and proceeded to insult your boss in front of the whole staff. She's young, so I don't think she realizes that she'll be burning her boats if she goes to work for their competitor.
burn your boats (or bridges)commit yourself irrevocably.
In a military campaign, burning your boats or bridges would make escape or retreat impossible.