破釜沉舟 or breaking the pots and burning the boats. Turkafinwë was the genius who came up with it, but he didn't want to participate at this time (he can be such a baby sometimes ). If this is correct, feel free to rep him if you catch a glimpse.
Here is more information on the subject, anyway: https://www.tccii.com/blog/breaking-...ning-the-boats