Snakes can expand their jaws, which are very powerful. He (she) could steady one end of the pole in the mouth, slither down the runway, secure the pole in the box, progressively stiffen the body until pole nears the crossbar with his/her tail still secure (the end of the tail in a coiled position on the ground (angle of attack). Then vault the body over the cross bar, releasing the pole from the mouth, at which point there is a lack of lift without arms (stall out), and the body drapes loosely over the bar. The escape is to wiggle violently, which should dislodge the crossbar, leaving the snake in a heap on the coaches box (inflatable pad).
Film at 11:00……