He wants to tell Clark that he shouldn't have his back, that he should be able to be objective about Bruce if anything goes wrong-- but it'll just be an argument. He has to trust Clark, and believe that he'll be able to make the right call in a potential bad situation. Jason, Bruce thought, might have been able to. He was there waiting to see how it would go, but after their fight-- would Jason have been able to kill him even if the Joker had won? He doesn't know. Seeing the way he's speaking to him now, what if he had just been watching for the chance to see Joker again.. he feels so tired, suddenly.

Bruce leans forward and kisses Clark, hard, like he's reaffirming that they're both here and alive and all right, his hands gripping the other man's shoulders. I need you and I wish I didn't he thinks. He should be strong enough to deal with this on his own, he shouldn't be dragging Clark down with him.