Losing his right arm, Obito hurriedly put some distance between himself and Naruto. At this point, he had reason to suspect that Naruto's previous Shadow Clone being absorbed into the Kamui Dimension was actually intentional!
Otherwise, with Naruto's exceptional reflexes, his Shadow Clone should have been able to use the Flying Thunder God Technique to dodge away before being sucked into the Kamui Dimension.
Yet the reality of the situation was that Naruto's Shadow Clone had been forcefully dragged into the Kamui Dimension by Obito without even using the Flying Thunder God Technique!
Chapter 122