Indeed, to avoid the anihilation of the 24 divisions inside the pocket (the whole VI Army, half of IV Panzer Army and bits of Romanian III and IV Armies) there was only one choice: to break out though the thin Russian infantry lines with the last mobile forces available. But the hesitation of the High general command made it impossible. All the corps commanders, lead by general Von Seydlitz-Kurzbach agreed that immediate measures must be taken. But general Paulus refused because he was going to obbey the general command's orders. Later, when operation "Winter Storm" was launched Von Manstein yelled Paulus in the phone and ordered him to try a break himself because the other half of Hoth's IV Panzer Army could not advance an inch more. But Paulus had Hitler's orders of not a step back and he knew that his men were not strong enough to go out. Much later, Paulus, when he saw the misery and suffering of his men he decided to try a break out, but Von Manstein refused to accept responsability and help him. At this time, Von Manstein was performing his master strategy and could not do anything to save the VI Army. Operation "little Saturn" of the Red Army had menaced Rostov and even a huger encirclement. Von Manstein was decided to take Kleist out the Caucasus: 450.000 men. 250.000 men inside Stalingrad were going to be sacrificed to save those other 450.000.
