According to Diwu Qingrou's tentative plan — Jing Menghun would've led his troops and killed King of Hell Chu at the last moment. Then, he would've created obstacles for Iron Cloud's army. He just needed to delay the enemy by one or two hours; that's all.
This was possible. In fact, the three-thousand experts were far more skilled than ordinary soldiers. They could easily set-up roadblocks to block the cavalry soldiers if all of them participated in their destruction. It was rather easy to pull this off in the mountain-forest. They could randomly cut down a few giant trees to achieve this goal. Moreover, Diwu Qingrou had ordered them to burn down the entire mountain-forest. This could've worked towards creating an atmosphere of panic and menace.
