Star Wars: The Last Jedi - 39 Things We Learned From The Director's Commentary
23. Force Connections
One of the film's biggest new additions, which also lead to some of its best moments, is the visual representation of the Force connection between Kylo Ren and Rey.
Johnson knew he needed to delve more into the Kylo/Rey relationship, but couldn't think of a way to get them together that wasn't contrived. What he wanted was to make them talk, so he thought of opening a new kind of connection between them, that would be intimate, rather than about the effect of how it was done. That led to dropping the sound to isolate them in these moments, and just using film grammar to communicate what was happening.
Adam Driver was off-camera in Ireland when Daisy Ridley was filming her parts of the conversations, and Ridley was on-set with him when he filmed his. These scenes were always the first thing Johnson wanted to watch back in the edit room, to see if the "magic trick" was going to work.