Definition
To start behaving in an unacceptable, dishonest, or illegal manner; to deviate from normal or acceptable behavior.
走向歪途，行為失控
He started to go off the rails after losing his job.
他在失業後開始行為失控。
The company went off the rails after it started making unauthorized trades.
這家公司開始進行未經授權的交易後就失控了。
She had always been a good student, but lately, she seems to be going off the rails.
她一直是個好學生，但最近似乎開始行為不端了。