What's funny is that I watched the "Legendary Commentary" on YouTube and they remarked that it was important for them to carry over details from the gameplay (shields) into the cut scenes. Like, when Emile gets the sword in the back, you can see his shield popping.

I would be okay with that restart theory if Bungie had at least paid it some lip service. They didn't have to go into a long explanation. Just a line, an utterance, a clue. Either they didn't think of it or they didn't want any exposition to intrude on their little moment. They always overestimate the impact of their little moments.