Quite a bunch of trolls here
Given that he had the knife in his pocket, we can safely assume that it was nothing big enough to be called "weapon", not to mention "deadly weapon" (or the guys in red are real wussies).
Given the target, the tasers should have been considered as DEADLY weapons, and thus not used. (I know, noone died this time, but people don't always die when shot either, guns are still deadly weapons.)
"it doesn't matter how good you are, you're going to get cut. Ok, a slash or two across the forearms....." Sure, you're going to be cut. If it's one on one, if your oponent is mobile, if you're unarmed, and wear a T-shirt. When it's 3 on one, your oponent is barely able to move, you wear a pair of heavy leather gloves and a solid uniform jacket, and own a stick, if you get harmed in any way (even a light scratch) it means you have nothing to do near physical security duties.
The old perp probably needs to spend the rest of his live in prison though, you're right Ima. After all, he has been a bad guy, no matter if it's due to his medical condition. Some of us have been scared by patients going postal, it means obviously that everyone raising his voice in an hospital should be shot on sight. And the mounties should get a medal, too. I mean, they probably saved the free world by tazering this old-timer...
Disclaimer: I'm fully aware that the old guy might well have been physically impressive (it's not like he was a former beancounter) but we're not talking about an old granny afraid that her purse might be robbed, we're talking about 3 well trained cold-blooded anti-riot cops. No excuse.