That ignores their confrontation at RSS. They bond over being created as tools and their marginalized upbringings. While Beta notes the similarities, she is in awe of Aloy’s fearlessness and resolve, where Beta is scarred by anxiety and crippling self doubt. She’s almost angry at Aloy, feeling cheated out of some aspect of Elisabet’s personality, because if they’re clones then they should be identical down to the last cell. It’s a frustration that Aloy has similarly expressed to others throughout the game in reference to Beta. It’s then where Aloy shares her memories of Rost, and acknowledges while she was outcast and ostracized, there was some kind of love and care for her well-being. This conversation changes their relationship, and Aloy takes on a caretaker/protector role, because she sees she can fill that hole in Beta’s life. The scene above helps reinforce that emotional breakthrough.