Lincoln and Veronica are seen (in a flashback) lying in bed, and they start kissing. When the shot changes perspectives, the orientation of their heads is reversed.
T-Bag, his cell-mate and Michael are in T-Bag's cell. His cell-mate is holding both the long screw and the stick in his hand, going to put the stick in Michael's pocket, but when his hand reaches Michael's pocket - the screw is gone.
When Michael is thrown over the railing during the riot, his stunt double is clearly visible.