If I were within yards of him and a security official, I would interpret his non verbal physical actions as hostile and threatening.
4 or 5 times he lifts his weapon in the air, pointing it almost at officers.
More than enough justification to take him out.... Lethally or non-lethally
Sir law is simple as the taught in police:
Dafa 99: nahi nahi, if the persons jesters are not threatening a person of imminent thread to life, or threat to property or case of izzat zany bil jabber the. You can't use lethal force.
Dafa 100 ; Hundred "Han Han" if the jesture or actions of the person are life threatening, or immediate loss of life, izzat, zany bil jabber then lethal force is justified.
Even in this umbrella you have to justify level of force used. You can't shoot someone hurling abuse saying I was under imminent threat. Similarly if the weapon is in shakari position the threat is minimal and 99 not 100 would apply.
Now when we talk about use force in Pakistan, not USA:UK etc, here is te levels of force:
Level 1: Physical presence- te physical presence, uniform, appearance an demeanour deter criminals
Level 2: Verbal caution/ compliance - achieved by using assertive direct cautions and commands.
Level 3: Non aggressive physical interention: using hands to stop person by blocking path, redirection, intervention
Level 4: pain compliant locks and physical contact: joint locks, body locks, physical restraint
Level 5: non lethal force: tear has, batons etc
Level 6: Lethal force
Level 7: Kill Zone
Hope this helps, remember that this can move upon down level dynamically ad can be though of line a rubber band.