Rasurar means "to shave". While shaving is a common act, the way it's used in this song is quite unusual and intriguing.
The lyrics state, "Será porque no me dejaba rasurar" (It must be because I wouldn't let myself be shaved). This line, in the context of being taken away and subjected to electroshocks, suggests a loss of autonomy and a struggle against control, making a simple act like shaving take on a deeper, more unsettling meaning within the song's narrative.
"Será por Eso" is Caifanes at their gothic best, sung entirely from inside a locked room. The narrator opens with "Desde aquel día me trajeron para acá" (Since that day they brought me here), and never explains who "they" are or what he did. The whole song is him guessing at reasons for a punishment he can't quite name.Every verse ends the same way: maybe it's because he wouldn't let them shave him, because even the ants stopped talking to him, because he keeps drawing on the walls. "Por eso me pongo un saco, Tomo la navaja y salgo a clavar" (That's why I put on a jacket, I take the blade and go out to stab) reads like a straitjacket and a threat rolled into one couplet, and the chorus answers it flatly: "Será por eso que me dan electro shocks" (It must be why they give me electroshocks). Saúl Hernández never says "asylum," but he doesn't need to. The shrug in "será por eso" (it must be because of that) is the whole horror of the song: a man who has stopped asking why and started inventing his own explanations for the machine that's grinding him down.