Inside Man (2006) - 3 questions

Question: This movie left me with more questions than answers. Even after watching it more than once. 1.) Was the fake wall built during the robbery or before? If it was built before, how was this done without the bank employees knowing about it? 2.) What was the purpose of the hole they dug in the floor? I thought this was where they stored the diamonds, but Clive would have had to tear up the floor and dig them up again later, which doesn't make sense. Why couldn't Clive have just brought the diamonds with him behind the wall during the escape? 3.) Wouldn't it have made sense to give each person who came out of the bank a lie detector test to try and weed out the ones who may have been involved? I realize that those tests are voluntary, so that in itself may have helped the police.

Answer: (1) The fake wall was constructed during the robbery - that's why they dragged things out, to give them time to finish the job. (2) The hole in the floor is so that Russell has somewhere to go to the toilet, serving the dual purpose that (a) he doesn't have to sit among piles of his own excrement for a week and (b) no unpleasant smell will build up in the storeroom, which could lead to his discovery. (3) Polygraph tests are notoriously unreliable and can be defeated by a suitably disciplined individual. As a result, the NYPD do not use them as a matter of policy. Even if, in this fictional storyline, they did, the unreliability of the tests and their tendency to give false positives is sufficiently well-known that it's likely that many of the witnesses might refuse to avoid the possibility of being incorrectly incriminated by a bad reading. So it wouldn't be likely to help them much anyway and could actively harm their case if it indicated somebody innocent.

Question: Was the bank employee who was taken into the back room and "beaten" one of the robbers? If not, was he actually hit or was it fake like the "shot" hostage? I couldn't tell if he was one of the ones in the car at the end.

Answer: The beating was real and no he wasn't one of the robbers. The men who participated in the hold up along with Clive Owen's character were all much younger than the employee who was beaten up. The much older guy in the car was not part of the robbery.

Question: Obviously I missed a major plot point, so hopefully someone can answer this. How does Dalton Russell know what Arthur Case has in the safety deposit box? Theoretically, only Case would know the highly incriminating contents of his own box. How did Russell find out? Did someone (the rabbi, maybe?) rat out Case? And how did he know?

Answer: There are groups who have spent their lives tracking down those Nazis and their allies that escaped justice after the war. While the specifics are never spelt out, it seems likely that the Rabbi represents one of these groups, who have presumably been watching Case for many years, trying to find incriminating evidence. They may well, for example, have infiltrated one of their people into the bank as an employee - they could have alerted them to the presence of the unlisted safety deposit box, leading the group, via Russell, to stage the 'robbery' to determine what was within.