Plot hole: There is no reason for the prison guards to use portable computers in full view of the inmates to input the sonic deadline code. The guards can walk outside of the deadline whenever they need to input the code, or radio the guard on the outside to lower and raise the deadline like they do when bringing the workers out. In fact, this plot hole is compounded by the presence of the guards stationed outside of the deadline with their own computer, which makes the guard inside the deadline completely unnecessary. The interior guard is only there so Weiss has a way to get both the code and a computer, but this prison set-up makes absolutely no sense.
Suggested correction: The point of having a portable on the outside and inside is in the case of an attempted prison break, if one of the computers is taken by the prisoners, the other can be used to prevent the deadline from shutting down. This was actually shown in the prison break scene where Weiss was unable to shut off the deadline with the inside computer was because the guards on the outside one were countering any attempts to close it.
That only explains why there is a guard outside with a computer. There is no reason to have a guard on the inside of the deadline with a computer. There can't be a prison break if there are no guards with a computer on the inside, the inmate's heads will explode if they cross the deadline.
Continuity mistake: As Richards and Buzzsaw are trying to overpower each other with the saw between them, the angle of the saw changes between shots. First, it's over Ben's left shoulder, then over his right as Buzzsaw talks. Also, when Buzzsaw talks, you hear the saw revving, but the chain isn't moving.
Continuity mistake: When people are walking into the building before you see where Amber lives, she is wearing her white robe and watches the news report that Richards shot the people at the airport at 'point blank range'. She says, "But that's not true!" and you can see Richards walking into the building wearing his work clothes at the bottom left corner. That scene had already been seen when Richards went to find his brother Edward, who lived in Amber's room previously. (00:27:53)
