He was arguing with Bruce about how Bruce didn't kill joker even after everything that lunatic clown had done, all the pain that man had caused and will cause in the future..

In this argument he grabbed joker and held him at gunpoint

If you won't kill him, I will.

He says with anger in his voice, Bruce's eyes widen and in a panic he threw a battarang at Jason's neck making him bleed heavily, not really meaning to hit him there but he did..

Jason groaned trying to stop the bleeding, he watched as Bruce grabbed the joker and attempted to leave the building without him..it hurt knowing that Bruce would never choose him over his morals or anything else.

So instead of trying to escape the building which had a bomb ticking inside of it he kneeled down on the floor and waited.

Did Bruce just choose that lunatic clown over his own son..?