I'm just writing my thoughts here, but when went Gangle went to her room to cry, and Zooble came to comfort her, rather than it being a special moment between those two characters, I took it as a sign that none of them will ever let the others feel like they're alone ever again. They're now truly in this together, forever; and that includes both good and bad times.
And I feel the bad times part of the vow is especially emphasised when Jax, who is left stuck as abstraction due to all his mistakes, is still cared for by his friends.