First of all, this is just a question based on my curiosity. It can seem pointless and illogical because of some missing piece of information, but I am asking it anyway based on my understanding of the movie, so correct me if I am wrong here. Anyway, The question is:
When Marty comes back to 'Twin Pine Mall' at the end of "back to the future 1", he sees that Libyans are coming and he rushes towards the doc to warn him. Important thing to mention here is that he returns 10 minutes earlier than he left. Now after he returns, he sees all of the events that have taken course including doc getting shot, Libyans firing and himself getting in the DeLorean and vanishing into 1955. During those 10 minutes, we see that there are 2 Marties existing in the same timeline.
Now this is where I am also unsure but let's assume that the vanished Marty would go back again in 1955 and will do all of the things in the same sequence as he did before. This also implies that he will also return back to the future 10 minutes earlier than he left the second time and so on.
So the thing is, wouldn't that create some sort of a loop? And there will always be a Marty returning back to the future?.
I just want to know what the writers intended or what is the closest to what they intended