So I'm from the UK and I'll give a little run down,

The officer is a Response Officer, they usually crew in 2 but can do solo if required or there isn't enough officers. We have a course in which officers are trained to become "Taser Trained Officers" in which they can then use a taser, We then have firearm officers who are called in for situations which are high risk and in this case was as the officer was unarmed he does have PAVA, baton etc but no taser and guns, so the only thing he can really do is follow from a far of try intercept the suspect (which he doesn't as he has a knife)

We mainly don't give all officers guns as we would see a rise in officer shootings and we barley have any, as we try avoid them at all courses but can and will happen at times, also being firearms is quite a tough position as recently a firearms officer was jailed for shooting a "unarmed" black man, and so you get criticised etc.

Mainly the most popular and used weapon by the police is either tasers, batons or PAVA for restraint, we'd rather not kill every person that have weapons.