A romanização oficial oferece uma breve explicação. Em suma, nosso trio de heróis estava simplesmente preocupado demais para notar o DeLorean sendo tomado.
Além disso, com a conversão em hover, o carro também é muito mais silencioso do que um motor normal movido a gasolina. Além disso, o carro só desapareceu (subjetivamente) por alguns segundos.
And all three of them. Doc. Marty and Jennifer, were busy elsewhere, so none of them could see Biff take off in the DeLorean, or, a moment later, land the DeLorean in the exact same spot. He quickly got out to hobble away, too quickly, maybe, because his cane got caught as the gull-wing door swung down. The cane snapped in two as Biff struggled with it. He took the half he had freed and hobbled away, leaving everything like it was before - except that now Biff no longer clutched the silver bag.
Também podemos supor que qualquer som teria sido mascarado pelo hover-taxi saindo da área.
He [Biff] walked straight to the car, opened the door, and climbed inside.
What was the old guy doing? Was that his car? Fred decided he didn’t want to know. He turned the cab around and headed out of Hilldale.
O roteiro de filme indica que ele simplesmente esperou até que a "costa estivesse limpa" e Marty não estivesse a vizinhança imediata.
EXT. AT THE DELOREAN
MARTY, now back in his 1985 clothes, impatiently looks in the direction Doc went. Should he take a closer look or not?
Yeah. He quietly follows, leaving the DeLorean unattended and out of his view.
Immediately, BIFF, clutching the silver bag, comes up to the DeLorean, sees that the coast is clear and opens the driver's side door.