You're right about the second timeline being in 85. I don't know why I thought it was 2015. Guess the coffee hadn't kicked in yet.
I agree that he stepped forward in time a bit to see what happened. As for the time machine not being invented if he had been committed. The time machine was a theory he came up with back in 1955. Maybe it was already invented in 83, just not tested.
Wait...that makes no sense. My heads starting to hurt.
If Doc had been committed, why did the Doc from the original 1985 simply disappear when they arrived in 1985A? Which then in turn, Marty, Jennifer, Einstein AND the time machine would all disappear. Thus negating all the changed forcing a universal paradox which would rip the very fabric of time and space.
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Something like that.
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I need a drink now.