Headscratchers / The Manhattan Project

• Several characters with advanced understanding of physics attempt to remove the door of the device that gives access to the core. The door has large grooves that they could leverage, but nobody seems to have a high school level understanding of torque.
• When Paul runs into the lab and begins assembling the bomb, why don't the Feds gang rush him? They know it's not assembled and even know how many pieces it's in from the Xray.