So, parallels.
(I got this idea from the video linked above, which also happens to show the panels, and wanted to "analyze" it! - asphodel)
In a prior panel, the reader can see Mugman pushing Cuphead away. At this point, its more of a flashback and the cups are children, arguing over something very mundane that i can't recall. Cuphead storms off, and Mugman is left to his own devices for ~3 days before Cuphead comes back. We see at this point that Mugman has genuinely never been without his brother, EVER. (prolly because their twins, stupid !) The sudden change in environment clearly throws him off as he starts panicking, and it starts to check the viewer in that they've been inseperable SINCE BIRTH. They've clearly never been separated, and at this frame is when it finally starts to show. Then the story shifts back to the present, where the next panel shows us Mugman reaching for Cuphead rather than pushing him away as he did previously. This is likely because Mugman has just briefly realized he's killed his own brother and has barely any time to process the decision he's chosen before its effect has taken place.
so thats my story.

















