Derrumbar means 'to collapse' or 'to fall down'. It's a strong verb that conveys a sense of destruction or breakdown.
In this song, Santiago Cruz uses it metaphorically to describe emotional turmoil. He sings, "Que adentro todo se derrumba" (That inside everything is collapsing), illustrating the profound emotional distress and internal chaos he feels due to the absence of his loved one. This powerful imagery makes the word particularly impactful.
Santiago Cruz's "Otra Mañana Más" [Another Morning] is a heartfelt plea from someone who's really missing their ex. It's another morning, and they're still not there, and our singer has "perdido la cuenta" [lost count] of how many times they've tried to call. The city feels gray, and everything is spinning because trying to forget them just isn't working.
He's practically begging them to "Ven" [Come] back, directly and without beating around the bush, because "adentro todo se derrumba" [everything inside is falling apart]. He admits they both know "de quien fue la culpa" [whose fault it was], but he's hoping they can learn from the past and try again. He's desperate for them to "venir para salvarme" [come to save me], even though he doesn't know where they are, and has "perdido tu rastro" [lost your trace]. It's a really honest look at that feeling when you just want someone back, even if it's complicated.