Why did the Red Army break through the natural barrier in Jiaoping for seven days and seven nights?

On May 3rd, 1935, the comrades of the cadre group of the Central Military Commission accepted the task of robbing Jiao Pingdu. Without saying anything, they crossed the mountains and mountains, and traveled day and night 180 miles, and arrived at Jinsha River that night. They were lucky to find a boat at the ferry. It turned out that the ship sent spies to the south bank to inquire about the situation, and the spies did not know where to go. Later, with the help of local farmers, they fished out a broken boat from the water and blocked the leak with cloth. Then, they quietly crossed to the north shore in these two boats. The enemy sentry thought the spy was back and didn't care. They suddenly attacked, wiped out a regular army and a security guard in one fell swoop, and took control of the cross-strait ferry in Jiaoping. Later, they found five more boats and mobilized 36 ferrymen. At the same time, the Red Army Corps arrived at Longjie Ferry and the Red Army Corps arrived at Hongmen Ferry, but there were no boats at these two ferries, and the river was too wide to bridge. The CMC ordered them to quickly move to Jiaoping to cross the river.

Edit the results of this paragraph.

From May 3 to 9, seven days and seven nights, the main force of the Red Army crossed the river calmly in these seven boats. After crossing the Wujiang River in the south, the 9th Army Corps, as a defender, has been hovering in Qianxi under the orders of the Central Military Commission, shifting from east to west and from south to north, thus containing some enemy troops. On May 6th, he arrived between Dongchuan and Qiaojia County, and successfully crossed the river in Du Shujie on May 9th. Two days later, the enemy pursuers reached the south bank. However, the Red Army has already destroyed the ship and closed the river, and gone far away without a trace.