壊れる?という質問がQuoraで。
The window regulator had snapped from the force of the slam and the resulting fall cracked the window. And of course BMW windows and window regulators are not cheap.
Daniel Lelis's answer to If you slam shut a car door, does it cause any damage? - Quora
これはBMWの宿命。ガラス押さえてるプラスチックのパーツがしょぼい。外れやすいんだよね。
窓落ちだけなら直せるけど、窓ガラスが落下で割れちゃあタダじゃすまないよなぁ。