Question: Did that officer who Vader attempts to choke, throw up on the table afterwards? I can't tell if that's vomit or just some buttons on the table, but as I haven't watched the film in some time, any help would be great.
Chosen answer: Every person on the table has a monitor in front of them, and what you see is a yellow button or some kind of mouse or joystick that glows.
Answer: When I was younger, I also thought the same thing. What appears to be 'vomit' is a reflection of his hand moving behind his face on the tabletop. My guess would be it was one of those little 'mishaps' that no one noticed and never thought to edit it out. The other for me was when Luke and Leia used the cable to cross the chasm, and right as they reached the other side, there is a brown smear on the lower backside of Leia's gown (my father once joked that the swing scared the ^&% out of her).