Simultaneously with the thrust at the roadblock, small enemy teams probed Fox Company’s line on the spur of Northwest Ridge, vanishing into the night after each light contact. These disturbances in the center of 2/5’s zone enabled CCF infiltrators and grenadiers on the northern tip of the spur to crawl undetected within a few yards of the limiting point between Company F and Company E on the right. Bugle calls cut through the darkness, and the grenadiers began heaving their missiles while the submachine gunners opened up. The din of this first attempt to unnerve the defenders lasted several minutes. Then came a sustained mortar bombardment of Marine front lines. While the shells rained down, the Chinese opened fire with crew-served automatic weapons emplaced all across Northwest Ridge. At 2125 the mortar eruptions began to walk toward the Marine rear. Whistles screeched, enemy machine guns fell silent, and the first Chinese assault waves hurled themselves against the juncture of Companies E and F. The enemy attacked on an extremely narrow front in order to maintain control. His troops advanced in column within grenade range, then deployed abruptly into skirmish lines that flailed the Marine positions ceaselessly and without regard to losses. The machine guns and rifles of Companies E and F piled the attackers in grotesque heaps up and down the front, but the pressure of human tonnage was unremitting. Ultimately, the Reds broke through on the northern tip of the spur, where the two units were joined. They poured troops into the gap, and as they attempted to roll back the newly exposed flanks, they overran part of Fox Company’s right wing platoon. Captain Samuel Jaskilka, commanding Easy Company in the draw, dispatched a light machine-gun section and a squad from his 3d Platoon (deployed in the rear) to reinforce his 1st Platoon at the edge of the breakthrough. The latter unit, under Second Lieutenant Jade L. Nolan, held firm and bent back its left to prevent encroachment on the rear. Staff Sergeant Russell J. Borgomainero, of the 1st Platoon, deployed the reinforcements to contain the penetration, while 2/5’s 81mm mortars laid barrages on the salient. At 2215, as the attack against Companies E and F was reaching its height, Lieutenant Colonel Roise ordered H&S Company of 2/5 to deploy for the immediate defense of his command post. The Chinese, blocked in their attempts to get behind Easy Company, continued to stab at the rear of Fox. If their envelopment succeeded, they could swarm over the headquarters and supporting arms positions of the 2d Battalion.