>>530042601
There was no self defense, and Meursault goaded the guy into pulling out the knife by approaching him, while he himself was perfectly aware he was being super fucking retarded for coming closer step by step, against a guy who obviously feels threatened by his present, and knows he has a gun, Meursault wasn't thinking straight.
What he did was pull out the knife and move his hand upwards to show he still had it as a sort of "back off", the sun flashes no the knife and hits his eyes, it makes all the sweat building up on top of his eyes fall, and he sorta blacks out in the moment, and fires.
When he comes about again, he notices he had not only shot the guy from far away, but he also fired multiple times again after coming right on of him, like an execution.

Even then, he could have gotten out of it if he had given a likely excuse, since France didn't really give that much of a shit about Arabs at the time, but he was too austitic and said "The sun was hot" or such, cause he himself didn't understand why he went that far.