This chapter made me realize that their relationship is like that of a bickering old married couple who despite saying they 100% despise each other refuse to leave for seemingly inexplicable reasons.
And then you realize it's because they're the only people that will tolerate each other enough to not rip the other's throat out after a single day. Well, more like Alvin is the only person that can tolerate Karla, but you get the point.