In the final scene Henry Talbott shatters the one-way mirror. Interrogation room glass is usually made stronger. When Eames and Goren are seen talking in the room from the observation room through the broken glass one-way mirror it is clear with no tinting. one-way mirror is dark when seen from the viewing side.
When Eames is in the interrogation room with Talbott, while letting him come onto her in order to show Mrs. Talbott what her husband is like with other women, Eames starts to flip a page on her legal pad. Before she completes the page flip, the angle on Eames changes from front to back, and the page is completely flipped and folded under the pad.