Ever annoyed by a program/installer asking you to "Restart Now"?
I am! Always! The solution is quite easy, although not in the means of the application’ developer.
Simply hold ⌥ down while clicking the Dock symbol with your right mouse button (alternatively hold ⌃⌥ and perform a normal click). A new menu entry will appear saying “Force Quit”. This will quit the installer immediately without needing any interaction, e.g. a restart.
The obvious downside of this is that you will have to restart your machine at some point to get the updates installed.