"How much time do I have?" asks the presenter and 5 seconds are wasted. An unintelligible response comes from somewhere in the audience. He then follows "Let’s see, what else I can show you ..."
You do not have time to start with. Time is a resource. In fact these days, time is a scarce resource, and when you deliver a presentation you consume this resource. People do not give you their time as a blank check. They give it to you for a purpose, and you should make the most of it.
There used to be a time when information was hard to get, and hence spreading this information was more valuable than the form of presentation. Today, this is no longer the case. We are bombarded with information, and hence value shifted towards its presentation.
Asking about how much time there is left shows lack of consideration for your audience. Filling this time with whatever you can find on the spot, mostly shows arrogance because you assume that you have the prerogative to use the time of the audience as you see fit.
Never feel compelled to fill up time. Better be as concise as you can, and stop when you are done. You will receive gratitude.
p.s. When it comes to points of view about time and presentations, the first thing that comes to mind is a quote from Garr Reynolds:
I’m not after saving my time, but after saving the time of my audience.
Garr Reynolds
The second thing that comes to mind is the computation of the price of scientific presentations proposed by Mircea a while ago.