It's for emergency.. if that happened to me I'd argue in court that I thought the driver went insane (because a system can't work like that) so it qualified as emergency..

But back to my country (Poland), it's better here - some had problems with physically getting out on the right station, and when the conductor saw it she even encouraged us to pull this lever in those cases so we don't have to get out at the wrong station.

Hyper-ventilate some, scream "Its too hot in here, I think I'm dying!" and presto-bango your very first panic attack and mental breakdown.