Attempted breach of duty without intent does not justify immediate dismissal under Polish Labor Code Art. 52.

The Supreme Court reversed the lower court's dismissal of the employee's reinstatement claim, ruling that the employer's immediate termination was unlawful. The employee, on medical leave, attempted to deliver keys to a replacement but entered the guard post while intoxicated, leading to his arrest and subsequent dismissal. The court held that the employer failed to prove the employee intended to commit a serious breach or that his actions constituted a 'serious' violation warranting immediate termination.