Mu You was sure of one thing: the man had nothing in his hand, yet the moment he pressed down his thumb, he vanished into thin air. Given the coincidence of the timing, Mu You didn't believe that this small movement had nothing to do with his disappearance.
In other words, the movement of the thumb could possibly be a switch to some kind of ability. Once activated, the opponent could retreat completely.
Mu You wasn't sure yet if this ability was related to him killing those pursuers.
If it was, then he might've found a method to restrain this person: control his movements, like what had been done to Taurus earlier, but more thoroughly, making his fingers incapable of any action!
Mu You didn't hide this method, and informed everyone present. After all, they were now adversaries, with the enemy openly declaring their intent to hunt them down. It was a fight to the death.
"Control finger movement?"
"So that's how it is …"
…
