when meursault encounters the lone arab, he is once againg overcome by sun's heat. what event does the heat force him to recall?

This is from chapter 5?

It's chapter 6, I will try to get you the text information.

This is the section you're referring to, but I don't see Mersault forced to "recall" anything here.

But when I came nearer I saw that Raymond’s Arab had returned. He was by himself this time, lying on his back, his hands behind his head, his face shaded by the rock while the sun beat on the rest of his body. One could see his dungarees steaming in the heat. I was rather taken aback; my impression had been that the incident was closed, and I hadn’t given a thought to it on my way here.

On seeing me, the Arab raised himself a little, and his hand went to his pocket. Naturally, I gripped Raymond’s revolver in the pocket of my coat. Then the Arab let himself sink back again, but without taking his hand from his pocket. I was some distance off, at least ten yards, and most of the time I saw him as a blurred dark form wobbling in the heat haze. Sometimes, however, I had glimpses of his eyes glowing between the half-closed lids. The sound of the waves was even lazier, feebler, than at noon. But the light hadn’t changed; it was pounding as fiercely as ever on the long stretch of sand that ended at the rock. For two hours the sun seemed to have made no progress; becalmed in a sea of molten steel. Far out on the horizon a steamer was passing; I could just make out from the corner of an eye the small black moving patch, while I kept my gaze fixed on the Arab.

It struck me that all I had to do was to turn, walk away, and think no more about it. But the whole beach, pulsing with heat, was pressing on my back. I took some steps toward the stream. The Arab didn’t move. After all, there was still some distance between us. Perhaps because of the shadow on his face, he seemed to be grinning at me.

I waited. The heat was beginning to scorch my cheeks; beads of sweat were gathering in my eyebrows. It was just the same sort of heat as at my mother’s funeral, and I had the same disagreeable sensations—especially in my forehead, where all the veins seemed to be bursting through the skin. I couldn’t stand it any longer, and took another step forward. I knew it was a fool thing to do; I wouldn’t get out of the sun by moving on a yard or so. But I took that step, just one step, forward. And then the Arab drew his knife and held it up toward me, athwart the sunlight.

A shaft of light shot upward from the steel, and I felt as if a long, thin blade transfixed my forehead. At the same moment all the sweat that had accumulated in my eyebrows splashed down on my eyelids, covering them with a warm film of moisture. Beneath a veil of brine and tears my eyes were blinded; I was conscious only of the cymbals of the sun clashing on my skull, and, less distinctly, of the keen blade of light flashing up from the knife, scarring my eyelashes, and gouging into my eyeballs.

Then everything began to reel before my eyes, a fiery gust came from the sea, while the sky cracked in two, from end to end, and a great sheet of flame poured

38

Albert Camus