He was a hard act to follow and what made things worse was that after he was finished a large proportion of the audience got up and left. It took at least 5 minutes for them to leave the room.
Which left the next speaker with a problem: to wait for everyone to leave or to start immediately.
If he waited for everyone to leave then he wouldn’t be able to give the full presentation he prepared. If he started immediately then he would be battling with the noise of the departing crowd and the distraction that it would have for the audience remaining, nothing that he says in those first 5 minutes would be truly heard and definitely not remembered.
The speaker decided to start immediately and it was a disaster, the noise of the people talking, shuffling their feet, the irritation of those who remained all combined to take our attention away from the speaker and his message was lost.
What should you do?
There is no other option. Your message is important and it needs to be heard. In order for your message to have the maximum effect then you need to start strong and to start strong you need to have the full attention of the audience.
But what if that means that you’re going to have less time to speak?
Then you have less time to speak. It’s not your fault, it’s not even the organisers fault as no-one could have predicted the huge popularity of the previous speaker but as a speaker you need to be able to adapt to different circumstances.
The key thing here is to concentrate on your core message and keep the sections that reinforce your message the most. You never know, you could end up with a presentation that is even stronger than the original.