The chapter on the nine grounds saved si di for last. Ground where you die unless you fight quickly. Sun Tzu treats this extreme separately and in depth.
We usually think that having no way back is what breaks people. Sun Tzu says the opposite.
投之亡地然後存,陷之死地然後生
tou zhi wang di ran hou cun, xian zhi si di ran hou sheng
Cast them onto ground of ruin and they survive. Drop them into death ground and they live. (The Art of War, Nine Grounds, translated directly)