If a client brings in a PowerPoint or Keynote file for their projection content and you want to pull the files out to use Qlab, follow these steps. These file times are essentially ZIP archives with different file extensions and program wrappers.
Make a copy of the original file so that you don't actually screw up the original.
On the copy, replace the .PPT or .KEY extension with .ZIP (you may need to open the Get Info window and then change the extension there)
You can then open the new ZIP archive and you will find a folder with the media files.