why do you think Paxton decided to kiss Devi during that moment in the car?
There is not necessarily a “logical” reason for the kiss, maybe it was purely physical.
But for me, this scene was the culmination of Daxton’s relationship in s1. The kiss probably happened because of the mood in the car, the sidelong glances, the confirmation that Devi like Paxton from Fab’s speech and their shared sense of familiarity and safety. Devi let herself be vulnerable with Paxton because she trusts in him. He has been somewhat of a constant in the craziness that is her life.
Maybe her vulnerability made Paxton realise that she is more than the “weird girl” in his eyes. Sure he was initially there for her because of their unique friendship. But along the way he realised he wanted more. That car scene solidified those feelings, he want to be there for him. He wants her to borrow his clothes. He wants to drive her home. He wants to be his confidant. He want to be more than friends.