Actually, let me boil it down further: If it involves multiple people being present, it probably should include them as well in this. What I'm safest and most comfortable with - for me and my character - is they weren't even on the same transport (there were likely multiples) and therefore the conversation doesn't need to occur, he likely didn't even see Obi with it, and you - therefore - get to keep the whole lightsaber thing safe and under wraps like you want it to be. That's all. :)