
This story already changed a couple of things with the Omegaverse. One was that not all bonds are in the form of a bite, and the other was that an Omega can come into being later on than in their second gender test...although I'm of the opinion he was just misdiagnosed like his friend was.
Plus the narrative where HeeSoo said he felt something open up inside of him while being knotted could also point to him potentially being impregnated. I read another story, Beast's Storm, where one of the characters basically said the same sort of phrase to his lover, indicating that his body was ready to conceive.
You all need to read up on what Omegaverse is. Exactly what is an Alpha, Omega, Beta and what they can and can't do. There's a couple good sites on Google. Try it....who knows, you might learn something (▰˘◡˘▰)