Question: When the 1985 Doc is suddenly transported back to 1885 at the end of BTTF 2 and Marty discovers that he has been murdered, because there is a Doc in 1955 that has already been born after the 1985 Doc has died in the West, why did he go to the trouble of going all the way back to 1885 when Doc was still alive? Is there any actual legitimate time travel reason for this, or did he just do it out of instinct to help his close friend?chunkz87
Question: Doc has always been firm about not wanting to create some sort of paradox. Was he not at all worried that eventually someone would go into his barn looking for him and find his giant refrigerator and his model railway with the car that said "TIME MACHINE" on it? I know he stayed behind after he rescued Clara so could have removed all that, but the original plan was he was going to hop into the DeLorean with Marty. We know he definitely left the model railway there as Clara picked the car up which prompted her to go after him.
Question: At the end of the movie, Jennifer asks Doc about the note she got from the future that became erased when Marty did not participate in the race with Needles. Doc's answer to her question is that her future had not been written yet, and he goes on to say that no-one's future has been, but if that is so, then how come in the previous movies he could travel into the future with Marty to see Marty's future?
Question: After Marty enters 1885, in his fleeing from the Indians, the DeLorean's fuel line gets ruptured and it loses all its gas. When Marty tells Doc this, Doc says gasoline doesn't even exist yet. However, Doc's DeLorean, which is now hidden in a cave, has its own gas supply in its gas tank and will not need it anymore, as 1955 Doc would just refill it after getting it out of the cave. Why didn't Doc siphon the gas from his DeLorean, and refill Marty's? He said the only problem at that moment was no gas. Not that he could not patch the fuel line, which would have been easy.Scott Miller
Question: For Doc to be so worried about corrupting the timeline in this movie (especially when it comes to falling in love with Clara) he surely doesn't seem to think twice about destroying the locomotive that will no doubt have a huge effect on the timeline. I doubt there were many trains on that railroad, with that mode of transportation now gone, Hill Valley itself could be wiped out.Carl Missouri
Question: When Marty and Doc are on the train at the end, and Clara shows up, Doc says that Clara will have to go with them to 1985. Why does Doc say that? Someone submitted a correction saying that Clara is better off in 1885 because she was supposed to die so staying in her own period is better than going to the future, so why would Doc suggest such a thing?
Question: Doc is a scientist right? The DeLorean had a ruptured fuel line and needed gas which, as Doc pointed out, was unavailable at the time. Surely he knew how to distill booze to make ethanol? (There was plenty of whiskey around at the time). I mean, they've used it to power cars in Mexico for ages. Why didn't Doc suggest this?Bodragon
Question: Doc Brown shows up at the end of part three with his wife Clara, his two boys, and a time-traveling, hovercraft-converted train. How did he build it? There was nothing in 1885 that could even begin to help him build another time-machine! And don't tell me that he used Marty's 'hoverboard' as parts, because that doesn't wash.CCARNI
Question: In 1955 when Doc and Marty are in the outdoor cinema and Marty is accelerating to 88mph to jump back in time to 1885, doc shouts something to him in celebration as Marty Drives past him, he also fires his gun in the air... Do you know what he shouts? The subtitles just say "shouts something in Spanish" but id love to know what he said and what it means?TDFarthing
Question: Why does everyone say that using parts of the DeLorean that Doc had buried in the abandoned mine could create a time paradox? Firstly, that is never stated in the actual movie. Secondly, if say Marty and Doc use the part on the buried DeLorean to fix the DeLorean that broke due to the explosion caused by the extremely strong alcohol and then again try to run the DeLorean using alcohol that's not so strong, the 1955 Doc would be able to obtain the missing piece of the buried DeLorean. So, technically, there's a plot hole. Why then does everyone say that that's not possible?