Jim and Sebastian having three entirely different conversations at once
Jim and Sebastian discussing plans together whilst one of them tries to get something out of the other by asking the right and clever questions
Jim and Sebastian knowing exactly what the other's on about, but still decide to play along
Jim and Sebastian needing not more than a few side glances, the tiniest bit of mimic and body language to know what the other needs/wants
Moran and Moriarty - A dynamic that isn't just only based on wanting each other, but a connection and understanding that runs and cuts deeper than a well sharpened knife.