Coming And Going

If I had had any consultative or advisory role when Poul Anderson's The Corridors Of Time was being written, then I would not have been happy for the text to go ahead without some elucidation of the question of duration within the corridors. When approaching a portal to exit a corridor, travellers walk along a line that corresponds to a part of a year in the outside world. While they are doing this, they should also see other travellers arriving through the portal and walking along or between lines corresponding to the same and to adjacent years. As it is, we are to understand that travellers are approaching the corridor from outside so why are they not being seen to arrive inside it? 

If, standing outside a portal, we see another traveller emerging from within and if we ourselves then enter the corridor, then, on our arrival within, we should see that other traveller exiting as we enter. I think. The external temporal interval between his exit and our entrance corresponds only to an internal spatial distance.

Nor do I see how these questions can be answered.