Responses
I dont know! Huhuhuu
My only guess is that maybe Gwanyeong's parents were one of those who opposed the experiment and because of that, some people want them gone
About the experiment flashback. It was mentioned that the esper doctor succeeded in creating a perfect esper. I dont know what happened to that esper though. It would be crazy if they suddenly linked to Gwanyeong lols

The one who currently 'occupying' the doctor's body is originally an esper. He is the one that wearing the eyeglasses from the flashback, right?
Then the body his occupying is originally a guide, who was the long haired brunette guy in the flashback. This guide was killed by that esper when he was caught having sex with someone after deliberately breaking the promise of pairing with him, the esper.
In the esper's despair whatsoever, he killed the guide, implanted his memories, kept the guide's memories and continue with his sick goal of finding a perfect guide to sickeningly pair with .So that's why the reason the center cant identify him as a guide nor an esper. He is a guide physically but have a mind of an esper. Okay okay okay... But what more sick is that he wants to pair with Taehun, a kid compared to his old freaking age!!! Ewwwwww thats pedo!!
Finally, the confusion was cleared. Pweeee