We have seen several instances where Harry or in specila cases his frineds survive several falls by using the "Arrestro Momentum" spell like in Prisoner of Azkaban and Deathly Hallows 2. But in Order of Phoenix, I observed they survived the fall without using the charm. Here is a screenshot of that moment:
So is it a unintended mistake from the producers? Or is it due to an omnipotent charm in hall of ministries?