Yeah but like, he wasn't exactly a superhero before, just a walking EMP generator with a little bit of physical strength on top.
Now he just straight no-sold a small caliber without a scratch, meaning unless the homies got a sniper rifle inside the mansion they are fucked
And not only that, did you notice that when he slapped that bodyguard, the hand actually buried into his skull? I mean, TCM has always been a magical drug, and I've always accepted the fact that realism in this series has little to do with the science, and all with the callousness and entitlement of rich people.
And speaking of the bodyguards… how stupid do you have to be to inject yourself with TCM when you know Sangwoo has taken four doses, three in the past few minutes, and is now able to dodge bullets and send people flying with the shockwave of his EMP? What do they think taking one dose will accomplish when normal people only get some strength enhancement? Is it really worth the salary? I'd have resigned on the spot and just left the house. But then again, these are not the "former special forces" kind of guard, they're more the "took some self-defence and minimal marksmanship training and then joined a dodgy private security company hoping for low-risk jobs" kind.