En Yahoo! Filmerartikel om Quicksilvers tillägg till filmen har ett citat från redaktören John Ottman, som förklarar att det inte är en vanlig Walkman utan en soppad prototyp som han stal:
How, in 1973, did Quicksilver possess that Croce-playing Walkman in the first place, given that technology didn’t emerge until the ’80s (and how does the music keep speed with him)? “Technically it’s not a Walkman,” Ottman explained. “There’s a whole backstory that’s never shown in the movie nor did we shoot it but he supposedly had stolen this thing that was a prototype of Walkman technology from some lab somewhere… So it was supposed to be some original prototype that he happens to have.”
Ottman laughs. “But how would anyone know that?”