A mercenary just blew up a Power Armor Knight head-on, what exactly is that concept?
It's probably like a three-year-old in kindergarten blowing up a thirty-year-old muscular hunk.
In fact, the enhancements that Power Armor brings to a Knight far exceed the gap between a muscular hunk and a three-year-old.
A three-year-old child coming at you with a knife could still score your leg.
But swing a sledgehammer at a Power Armor Knight standing right here, and the hammer will shatter before leaving a mark on the armor.
Designed as military technology, Power Armor was originally intended to replace tanks and other mechanical vehicles, with its most basic function being bulletproof.
Unless you use a specialized anti-materiel sniper rifle, ordinary firearms can't penetrate it.
Not to mention swords. To break Power Armor with cold weapons, you'd need at least Level 8 physical power.