Marty had to think - was there anything else Doc should know?
Oh, yeah. ‘I think the cops said they were gonna take her home,’ Marty added.
‘Home?’ Doc frowned as he steered the remote. ‘Great Scott! If anyone's home who recognises her -you, or your family - and they traumatise her - or worse, if Jennifer actually encounters her future self - the consequences could be disastrous!'
Disastrous? Jennifer? Marty didn’t like the sound of this.
‘What do you mean?’ he asked.
‘The shock of coming face to face with oneself -when one is thirty years older - could be so severe that she could pass out!’ Doc waved dramatically at the ground. ‘And if she were to fall, crack her head open and get killed, you two certainly wouldn’t be able to get married. If you don’t get married, you don’t have any kids. If you don’t have kids, I won’t have a reason to bring you both to the future in the first place, and if I don’t bring you to the future, Jennifer won’t get killed!'
So Jennifer would be all right then? Marty wasn’t sure he exactly understood everything the Doc had said, but that didn't sound so bad.
‘Then what’s the problem?' he asked.
‘It creates a time paradox!' Doc waved his arms agitatedly. ‘A person can’t be both alive and dead at the same time! It violates the laws of physics!’
Marty still didn’t see the problem.
'Doc! You can’t get busted for violating the laws of physics.'
Doc nodded grimly. ‘No, but such a thing could luse a chain reaction that would unravel the very fabric of the space-time continuum and destroy the entire Universe!’
He paused, considering.
‘Granted,’ he continued, ‘that’s a worst-case scenario. The destruction might in fact be very localized
limited to merely our own galaxy.’
Only our own galaxy?
‘Oh, hey, well.’ Marty tried to laugh. It came out more like a croak.‘That’s a relief.’
The DeLorean pulled in front of them. Doc glanced over at what Marty was holding.
‘What's in that bag?’
‘This?’ Marty asked innocently. Doc’s gaze was awfully intense - it probably had something to do with all this talk about destroying the space-time continuum. Marty tried to ahrug it off. ‘Oh, nothing - just a souvenir - a book that looked like it might be interesting.'
Doc took the bag from Marty’s hands. He pulled out the book.
'Fifty Years of Sports Statistics,' he read. ‘Hardly recreational reading, Marty.’
‘OK, well,’ Marty confessed, ‘I figured it couldn’t hurt to bring back a little info on the future, you know - in case of cash flow problems -’ He was finding it a little difficult to talk under Doc’s level glare.
I’d place a few bets -’ His voice trailed off. He tried to smile, but Doc wasn’t buying it.
Marty, Doc replied in his best lecturer voice. ‘I did not invent time travel for financial gain!’ He paused book still in hand, to grab the lapels of his lab coat. The intent here is to gain a clearer perception of humanity - where we’ve been, where we’re going, the pitfalls and the possibilities, the perils and the promise - perhaps even an answer to that universal question: Why?’
Doc paused to gaze nobly at the horizon. Apparently, he was finished with the lecture for the time being. But Marty still couldn't see what he was doing wrong.
‘Oh, hey, I'm all for that, Doc.’ he replied, ‘but what's wrong with making a few bucks on the side?’
Doc’s intense gaze once again shifted to Marty. ‘Because the risks far outweigh any potential rewards.’
Marty had been wrong. Doc was still in lecture mode.
Doc Brown put the book back in the bag and tossed it in one of the futuristic garbage cans that lined the alley. Marty sighed. He guessed Doc was right, but it was a shame to lose that kind of opportunity. He supposed he would have to find other, more difficult ways to keep his life from the toilet.