Stubborn bug
Building off something @iwillgetridofyourangerforyou said, now that you mention it, Genos is doing a pretty bad job of dying, isn’t he?Â
Why bug? Ah, thinking of himself in terms of a bug (nice metaphors he’s used for himself: woodlouse, dung beetle). Not to mention that bug monsters really keep bugging him, so much so he’s called it his karma. Never any nice critters, but all the ones associated with untimely death and/or decay. Why? Only ONE knows.Â
Anyway, back from that aside, this little bug is proving rather hard to crush, although it’s something Genos would dispute.
Being the sole survivor of a massacre? That he just attributes to a miracle.
Survived a body modification so radical that it’s well past the limit of what is considered survivable? Oh, he just has the best doctor in the business.
Black Sperm was shaken when he saw Genos come back with Saitama -- and has sensibly kept a lowish profile around him.  He was so sure he’d beaten this guy to death, not to mention Garou had kicked him around like a hackey sack.  Oh, he just has the best doctor...
If the manga follows the webcomic’s main points, that unexpected survival is only going to be more grotesque. Gouketsu literally crushed him and reported him dead. He got better. Elder Centipede had a go. He got better. His current body has no safety limits and is as much a danger to him as the monsters who will all be pouncing on him. See, his doctor is so good that even when he says he’s taken away the safety margins, he’s still looking out for him.
At what point is Genos prepared to accept that maybe, he just isn’t prepared to die? And that that intense desire to survive has a role in the fact that he’s still alive? Ah, we just have to wait and see how many more breakages it takes.
