4. You Don't Need To Keep Time Traveling If You Can Just Send Letters
In Back To The Future Marty faced a difficult decision of whether to tell the Doc that moments before he was transported back in time he had witnessed the older version of Emmet Brown gunned down. The younger Doc had warned Marty about telling him too much about his future, so Marty decided to write the Doc a letter which he could open in 1985. Doc proceeded to tear it up and Marty never got the chance to warn his friend of his impending doom. Upon returning to where he belonged Marty once again saw the Doc shot, but was delighted to discover that after leaving the past the Doc had had a change of heart and managed to retrieve the torn pieces of the letter, tape them together and buy himself a bullet proof vest. Why did he still allow himself to be shot? With his advanced knowledge of the future the Doc could have arranged to meet Marty anywhere else where the Libyans wouldnt have been able to find him and shoot him. Furthermore he could have stopped Marty getting trapped in the past. Whats that I hear you say? Preventing Marty from time travelling in the first place would have meant that he couldnt write the letter that warned the Doc and therefore create a paradox that would destroy the universe. Oh would it? The Doc doesn't seem to think so as he wrote a letter to Marty that he received at the end of Part Two. Had Doc not sent this letter then surely Marty would have been trapped in 1955, and who's to say he wasn't supposed to end up stuck there? Saving Marty from 1955 could have just as easily led to the destruction of the universe. This whole mess of what happened in Part Three could have been avoided if upon realising that they would get a petrol leak, the Doc had gone back down to Western Union and said that he wanted to leave an additional note with the letter he was sending Marty. It could have read "Dear Marty, if you do decide to come and rescue me make sure you have a gas can with a couple of extra gallons...oh and some chocolate digestives would be nice too." Problem solved.