Plot hole
I actually loved this movie despite its flaws. But I found a plot hole.
As the time change was like a layer, as you're passing through the layer, especially with such differences in time, you're going to have a few seconds where different parts of your body are running at different times.
Holy moly, I can't imagine what that would actually do to you. I would imagine instant death.
Obviously they had to just kinda leave this out to make the story work. But with the way they said they felt the air change, there was a distinct layer between times. Your entire body would have to pass through that layer instantly in order to avoid splitting yourself between different time speeds.