grave breaches meaning in English

严重违约情事

The signalman left his cabin before attending to his signals and so committed a grave breach of duty
信号员没有发完信号就离开了他的小木房，因此犯了严重的玩忽职守的错误。
" it is considered a grave breach of security rules , " a police spokesman said , adding that a prison guard or a police officer should have been on the tower at all times
“我们认为这严重违反了安全条例， ”警方发言人说，并指出任何时候了望塔上都应该有一名监狱警卫或是警官。