Sutter’s unit completed the passage of lines at 0900 and attacked along the boulevard with Fox and Easy Companies in the assault. Leading the advance up the street were the tanks of Baker Company, Cummings’ M-26 in the van. The young officer’s machine had proceeded only a few yards when it struck an American M6 mine, overlooked by Marine engineers while they were removing their hasty field of the previous night. Not only did the explosion wreck the tank, but it also caused several casualties among the infantry on either side. The attack edged forward in the second day of the “Battle of the Barricades.” Every 200–300 yards, fanatical Red detachments manned rice-bag barriers about eight feet high and five feet thick, stretching the whole width of the street. It fell to the M-26s to smash the emplacements and silence the NKPA antitank guns behind each one. Marine tank action in turn hinged on mine clearance by supporting engineers, who looked to flanking infantry for covering fire. Thus was a system of three-party teamwork developed and perfected during the roar of battle. Aiding the Communists behind the barricades were other North Koreans who fired their rifles and submachine guns from roof tops, windows, and side streets. The Marine infantry, therefore, had to defend in every direction as it attacked to the front. Intense heat from burning buildings along the street added to the handicaps, and the constant discovery of South Korean civilians, including women and children, huddled in the rubble further strained the taut nerves of men who looked for trouble from every quarter. It was a dirty, frustrating fight every yard of the way, perhaps best described by Puller himself, who reported that “progress was agonizingly slow.” A principal deterrent to speed was the fact that all supporting tanks simultaneously expended their ammunition and fuel, so that all had to return to the rear for replenishment at the same time. During their absences from the fight, the infantry understandably chose to await their return rather than pay heavily in casualties by assaulting barricades with small arms alone. At one point in the street battle, an enemy soldier darted from behind a building and charged a flame tank advancing behind two lead M-26s. Ignoring the Marine infantrymen, who gaped in disbelief, the North Korean hurled a huge satchel charge over the engine compartment of the armored vehicle, then escaped unharmed as the explosion rocked the area. The flame tank was wrecked, but the crew escaped serious injury with the assistance of supporting infantry. Apparently a suicide squad of NKPA demolitions men had been assigned the mission of destroying Marine armor in this fashion, for several other Red soldiers tried single-handed assaults shortly afterwards. The riflemen of 2/1 were alert for the later attempts, however, and the enemy fanatics were cut down before inflicting further damage.