‘YAAAAAAAH!’Doc shrieked.
‘Calm, down. Doc!’ Marty urged. ‘It’s me, Marty!
Doc shook his head wildly. ‘No! It can’t be you! I just sent you back to the future!’
Somehow, Marty had to explain all of this to the scientist.
‘Right!’ Marty replied, trying to be as logical as possible. ‘You did send me back to the future. But I came back - back from the future!’
‘Great Scott!’ Doc replied. He staggered back, clutching his chest. He seemed to be having trouble breathing.
‘Doc!’ Marty called. What was going on?
Doc’s eyes rolled up, and he fainted dead away.
‘Doc?’ Marty asked, but the scientist was out cold. The shock had been too much for him - one of those paradoxes that Doc Brown himself had told Marty about.
But how could Doc help him, if even the scientist couldn’t face the truth about the future? And what if it was worse than Marty thought, and he couldn’t revive Doc? Then the scientist could never build the time machine, and Marty would never end up back in 1955 in the first place.
That would be one of those real paradoxes, wouldn’t it - the kind that might put an end to the cosmos and all life as we know it?
‘Doc?’ Marty called, bending over his fallen friend. ‘Doc?’
But Doc didn’t answer.