When you run PyInstaller, it bundles an interpreter with all the necessary third-party modules, so there's no need to install things. What that cv2 example shows is how with very few lines of codes, an atacker can open the webcam and obtain 10 images (roughly 1/3rd of a second) of camera footage.

However, in all notebooks that have one, that code will make your litle LED indicator right by the webcam turn on, so it's not particularly quiet about it.