there are so many subtle things in this scene with the context of gabe being what he is

dan saying “i’m holding on and i won’t let go” as he tries to explain to diana that he wants to help her and not lose her, and then later dan repeats “i’m holding on” and gabe sings “and i won’t let go”

gabe’s laugh when diana starts yelling at dan

gabe pretending to be gentle and good as he holds diana’s hand

gabe throughout the show always wearing the same color as the person he’s interacting with and in this scene it’s the same colors as dan, not diana

diana running to gabe’s arms, and gabe mocking dan for that

dan, a man who has spent years denying his own mental illness, saying to diana “tell me what to do” and the personification of mental illness answering “look at me”