I've seen this debate about the outcome of the moving portal. I'm pretty certain that because of inertia, and the people aren't moving, they will just plop out the other side. Think of it like moving a hoola hoop through the people. That's basically what the portal is.

The hoola hoop has inertia and is moving, but it doesn't actually come in contact with the people, so it passes right around them. There's no way for the people to have instant acceleration because the porta did, otherwise it'd be like them hitting a brick wall and they would probably explode

A, the people are traveling towards the portal, not the other way around.

If they were falling/running at the portal it would be different.

Here the portal is moving forward towards them, they have no momentum.tk travel through the portal.

Someone take this a step further and make the train an airplane on a treadmill

The only way it could be B in this universe is if the train also decelerates equivalent to how the people accelerate. If the people accelerate and the train maintains velocity you've created energy in a closed system.

a portal is supposed to be like a hole that you go thru except you end up somewhere else, if i pass a hole over you, would you feel anything? A