Totality of infractions

Dear Atty. Maan,
We've been facing challenges with one of our employees recently. Despite having been reprimanded multiple times in the past and even receiving a suspension, this employee was caught violating our company's code of conduct once again.
Can we terminate a problematic employee who not only has an attitude problem, but also refuses to do tasks that are incidental to his duties without the risk of committing illegal dismissal?
Laika
Dear Laika,
In determining the sanction imposable on an employee, the employer may consider the former's past misconduct and previous infractions.
Also known as the principle of the totality of infractions, the Court explained such concept in Merin v. National Labor Relations Commission, et al., thus: "The totality of infractions or the number of violations committed during the period of employment shall be considered in determining the penalty to be imposed upon an erring employee. The offenses committed by the petitioner should not be taken singly and separately.
While it may be true that the petitioner was penalized for his previous infractions, this does not and should not mean that his employment record would be wiped clean of his infractions.
After all, the record of an employee is a relevant consideration in determining the penalty that should be meted out since an employee's past misconduct and present behavior must be taken together in determining the proper imposable penalty.
Despite the sanctions imposed upon the petitioner, he continued to commit misconduct and exhibit undesirable behavior on board. Indeed, the employer cannot be compelled to retain a misbehaving employee, or one who is guilty of acts inimical to its interests. It has the right to dismiss such an employee if only as a measure of self-protection."
Likewise, in Sugue v. Triumph International (Phils.), Inc., the Supreme Court stated that employers are not expected to retain an employee whose behavior causes harm to its establishment:
