burn your bridges behind you
To eliminate any possibility of a retreat to a former position: “In his ruthless pursuit of success, Sloane offended all his coworkers and effectively burned his bridges behind him.”
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.