If two signals that are mirror-images of one another are combined, they attenuate each other. This is often called “phase cancellation” (which in truth is a bit imprecise, but will do for now). You can demonstrate this cancellation easily in your DAW by bringing up two identical tracks and then flipping the phase of one by hitting the polarity switch, usually rendered with a symbol resembling “Ø.”
“FEFE”: Welp, almost none of the section lengths here are standard. The bridge is really like some kind of early outro that incorporates the refrain, and then the outro-outro also mixes in the refrain, just in a different way. Who even knows anymore?