What nice timing for a banker as villain!
But also what a tragedy.
The gamma-of-the-week (and I'm uncomfortable with that term because it undervalues the writing) isn't a villain so much as a victim, which we've seen before, but he breaks through to take on a real villain, he just does it in the wrong, possibly Bug-Influenced, way.
Nor is it clear if he's a Gamma, a Hafs-type Beta, a Hope-type Beta, or something new, a one-off because of the brain-damage. If he can't do abstraction, then can he do the paranoid/obsessive ideation that's how Bug manifests? And if he can't do that, can we call him a Gamma or Beta? The appetite from birth suggests Hope-type Beta, but I'd like to see the genetics on this one!
For a gamma he's very task-oriented (why yes, I am watching a lot of CM re-runs at the moment

) , more so than most of the gammas we see. It's rare to find one with a plan that stretches beyond the next manifestation/atrocity. Hope springs to mind (though she was a Beta, of course), and beyond that we have the puppeteer(s), but other than that I'm coming up largely blank. Felicity Tabor had a goal, but not the first idea of a plan. Erik, on the other hand, is staging manifestations as an arrow shot straight at his father's powerbase, there's a purpose to everything he does that we rarely see.
'Bulletproof', of course, had us all scared for Nikki, and she's clearly still fragile, but she's also clearly still Wonderwoman, dropping her gun into Reyes' hands to hug the gamma into submission - it makes some of Reyes' more crazy bring-em-back-alive moves seem positively pedestrian! And there at the end she finds the approbation she's been looking for from her father, everything she wanted from him when he was alive, denied to her until he was gone. Tragedy again, though with a seed of hope buried with it.
No hope for Erik, though, physics one, gamma nil, but maybe that was what he wanted. That final assault on his father's building, and his testament, bear every sign of being a suicide run, stepping off the roof may be just more of the same, suicide by cop for the man who can't be shot. Difficult to see this one as anything more than just plain tragedy.