The girl that started the crash got away without crashing.
At the 0:20 mark you'll notice a woman go sharply up-track (up the track) and a second woman follow her. That second woman isn't following her on purpose. Her front wheel is overlapped with the first woman. The second woman is holding on for dear life and eventually falls starting the chaos.
The move by the first woman is unusual and totally ill-advised and unexpected. Every time I've seen that move it caused (or almost caused) a wreck.