Uttering or even verbally threatening another employee or to make things worse, to one's superior is a major misconduct. Some may say that they did not mean what they say but still, the incident has happened. Such act is also consider insubordination, as the said action is not a required or desired action of an employee of any company.
Briefly, abuse is not limited to physical assault but verbal assault as well. Especially threatening statement that is seen to be a gross misconduct that risks others’ safety.
And on the grounds of insubordination, an employee MUST NOT disobey any legal instruction which is also considered as gross misconduct.
Another case cited is Ngeow Voon Yean v. Sungei Wang Plaza Sdn. Bhd/Landmarks Holdings Bhd.  3 ILR 1717 where the court stressed –
“From the case law, it is clear that the duty of obedience is confined to compliance with the lawful and reasonable orders of an employer and as such the concept of an order being manifestly wrong has no part in the doctrine of superior orders. To that extent the Court of Appeal erred when it made an exception to the general rule on superior orders when stating that an employee is entitled to disobey the orders of his superior if he, the employee, is aware that such orders are manifestly wrong. However, that exception holds good in military or criminal law as seen from the case of PP v. Tengku Mahmood Iskandar  1 LNS 124;  1 MLJ 128 where it was held that "a soldier is not protected where the order is grossly illegal."