Can we assume that this is the scene shown a few seasons ago when the bride requested the presence of the best man?
I think its going to be Robin asking Ted not to move. Im not sure why. I just get the feeling that Ted will not be moving. I dont think it will be because of the mother. I think he will choose not to move because of the "gang".
I know that him being at the station debunks this theory but... Hes not getting laid. So why stay the extra night? Also I think he misses the train hes supposed to be on. Thats how he met the mother. And at the end. The kids go... "So you met mom cuz you missed a train?" You could have saved us a lot of time.