Jason had already survived death once. It's no exaggeration to say that if he'd died immediately, he'd have been happy, but the Joker, being a vile creature, tortured him when he was just a child.
Now everything has changed, he has become stronger, taller, faster, better than Joker and knows for sure that he can put an end to all this. He doesn't need Bruce's prejudices that killing is wrong, blah blah. Whatever. Joker will ultimately die for revenge, even if it means nothing more than revenge.
The buzz spread throughout the city—of course, everyone knew about it next day. But what Jason himself didn't know was that Joker had a child the whole time, and blood feuds are always a hallmark of crazy.
Jason doesn't remember himself when he let out a grunt, feeling a burning pain throughout his body, he remembers being on patrol, but then everything suddenly disappeared. His eyes are completely blind because of the blindfold, so if he could do something to see, it's only darkness. It's so reminiscent of Joker's style because his legs and arms are also tied up just like clown did. A shudder of anger from these memories ran through Jason, causing him to frown and return to his chair, suddenly hearing footsteps and immediately exclaiming.
— "Hey! What the hell is going on here?!"
He jerked in the chair again, but in vain, at least he realized that chair was attached to the floor.