I think, "Just in here." I think he has a speech mannerism resembling a very slight stutter.
Her: "I don't really know that is ever is about the money. It's about the challenge."
Him: "How r--how rich are these guys?"
Her: "Really what they start with can be easily five million--and that's just their gambling bankroll."
Him: "Just-just in here."
Her: "Just in here."
Him: "Uh--Stroll out. Five million. Off we go."
I think he means that they are prepared to visit more than one casino and that the five million she is talking about means five million to be gambled in one night, one place, "just in here."