Originally posted by exanda kane
Nope, it's another gap in the plot and as usual everybody is reading way too much into these things.
Listen to everyone else, specifically darthmaul1, there are answers if you open your mind.
I myself assumed that when Yoda saw the security holo and heard about the Empire, that's how he knew.
Besides, Jedi mind tricks could have come into play in the hallway. (Joke answer)