"Thank you"
Mark wishes he had said that to John. A thanks for giving him inspiration to avenge his sister, a thanks for helping show him a better way to deal with the scum of the Earth.
"I promise…"
An unspoken promise to John, to keep John's work going as long as he could.
"I win"
The feeling Mark feels as he kills Agent Strahm. For the first time in years, things are going his way. John is dead and Mark feels in control of his own once again.
"You lied!"
The thought that haunts his mind as he breaks out of the Reverse Bear Trap. A thought that leads him along his vengeance to Jill.
"Game Over"
The last thing he hears before being locked away. Right now he's feeling helpless, and it's up to him alone to live.