I guess the most precious imaginary scene I have of the break trio is just these three chilling in casual attire and eating store-bought snacks maybe on the playground or the park.

Endou and Kidou are facing each other and talking about something mundane that are important to them-- sharing their hyperfixations of a cute show probably that Gouenji also watch-- and Gouenji just sits listening to these two, back against Endou's who is being mindful about his movements despite his excitement on the topic as to not ruin Gouenji's meal. Kidou talks animatedly with a wide smile as he observes how cute Gouenji and Endou are sitting like that. He never misses Gouenji glancing at him and Endou with a smile once-in-a-while.