Hi John:
One way to save time with PPT is to jump to the end slides if you have summary points already listed. This can also be done without summary slides - by just using the white board to put salient bullet points that are essential to the lesson.
If available, you can get a copy of the test or quiz and scan it to make sure you're going to cover the test information. This is less than desirable, but, as you say, when time is short, at least give them something helpful.
These are also times a teacher may want to reflect on why their time got away from them to avoid this from recurring in the future.
Regards, Barry