What do you think would happen?

The Afrikaans (Thomas Prescott) - Nick Pirog

to set the scenario, there's a cruise ship which has been boarded by pirates and all the passengers are hostages.  Rescue is days away, and the passengers have come up with a plan to take down their captors.

 

they've managed to kill a couple of the Pirates, capture some guns, then this happens:   all the passengers insert ear plugs, and . . . 

 

 

It sounded simple enough. Point the LRAD where you want the sound waves to go and everyone within the line of sight will be crippled. And everyone within a hundred feet of the sound waves wouldn’t be able to hear for a week. Maybe two.

 

Even with the earplugs, my head ached. It felt as though I was standing with my ear to the speaker at a Rage Against the Machine concert. As for the Professor, the Warlord, Rikki, and Bheka, all four were now on the ground, hands clapped over their ears, writhing on their backs.

 

The Warlord (pirate leader), manages to struggle to his feet, fumble for his knife, and cuts off his ears! 

 

And suddenly, the LRAD is no longer disabling for him.

 

So here's the question.  Can that possibly work?  (I could have looked it up, but I was curious about what you all would say.)