If a rider “goes through the window”, that unfortunate person has either been dropped or surprised by the group’s acceleration and can’t get back on. This happens in nearly every breakaway of any significant size, usually on a hill, or in the wind, like the poor Direct Energie guy below.
The Vicious Cycle 
Can you use it in a sentence, please?
You sound like me in my English classes! “Il passe par la fenêtre”
My window is always open.