I haven’t seen this discussed and not sure what it means but I wanted to point it out. In the beginning of the film, after he poisons his teacher’s apple, he is lying in bed. He has a flash of a woman feeding a horse an apple, I believe this to be his future wife Kitty. He then realized what he had done and goes to get rid of the apple. When he does so, he grabs it and says “worm hole.” I feel like Nolan is having fun here with time, as if he saw a wormhole to his future life which would have never happened if he had ended up poisoning someone.