When Marshall demonstrates the messaging function of Sydney's glasses he presses a button in the left temple. When Sydney later sends the message she presses the right temple.
When Sydney and Vaughn search the house of Dr. Viadro, Vaughn goes upstairs and Sydney continues to search the ground floor. Behind Sydney through the window someone else (presumably Michael Vaughn) can be seen shortly. This happens before the order of Rimbaldi arrives, so Sydney should have been alone on that floor.
When Lauren downloads the data from Marshall's computer, the long shot shows the download is complete or almost complete, whereas the following closeup shows the download at 38%.
When Dr. Viadro tries to open the panic room he tears down the keypad by mistake and pushes it back up. It is later opened by Vaughn with a screwdriver.