Then, I don’t know why, but something inside me snapped. I started yelling at the top of my lungs, and I insulted him and told him not to waste his prayers on me. I grabbed him by the collar of his cassock. I was pouring out on him everything that was in my heart. […] He seemed so certain about everything, didn’t he? And yet none of his certainties was worth one hair of a woman’s head. He wasn’t even sure he was alive, because he was living like a dead man. […] But I was sure about me, about everything, surer than he could ever be, sure of my life and sure of the death I had waiting for me. Yes, that was all I had. But at least I had as much of a hold on it as it had on me. (2.5.25)
This is the most active we’ve seen so far, and a big part of his revelation. By bringing in emotions of "anger" and "joy," by "yelling," Meursault breaks away from his old, passive self.