Telepathy or Illusions?

"Don't worry. You will know soon." Jack stated mysteriously. No sooner had he just finished speaking did Sylvia suddenly feel the effects of the serum kicking in.

Suddenly, Sylvia felt that her head had been suddenly been hit by something heavy and hard. For that reason, she felt somehow dizzy while at the same time experiencing a headache.

Other than that, she felt that in her mind, there was something that was trying to activate. It was a process that was filled with pain, something that made her grab her head tightly. It was just that she was trying to make sure that she did not scream due to the pain that she was currently experiencing.

The amount of pain that she was currently undergoing was tremendous. And had it not been for the fact that Sylvia was someone that possessed great will, she would have definitely screamed, asking for it to stop.