Who fired that cannon?

Dave was walking down the street one day, he'd never worked a job in his life and he was sick of it. So he marched straight down to the job centre right up to the counter and goes
'I want a job, any job you've got. I'll do it for you.' The girl at the desk flicks through some papers.'I'm really sorry sir we don't have that much at the moment.' 'Oh come on, surely there's something? Anything? '. Dave pleaded. 'oh, hold on. We do have a spot in an upcoming show. It's a bit short notice as the show is tomorrow. ' 'oh aye? What's it called?' he asked 'who fired that cannon? ' the girl told him. 'who fired that cannon? You know what, I'll do it!'

That night Dave took home his script and read all 256 pages of this play. Waiting for his part, he finally comes to the last page. And there it is in big bold letters. WHO FIRED THAT CANNON!? Dave gets quite excited seeing that he is the character who is going to finish off the play. He spends the night working on his delivery of the line. He tries it with a low scary voice, he tries it with a shocked worried voice. Hours later he has finally got it. And jumps to bed filled with excitement for the next day.

That night he is waiting in the sidelines talking to one of the cast. 'So how do you think it's going?' 'Yeah, it's good Dave, just watch the stage you're almost on.' 'Aye don't worry I'm watching. You doing much after this?' 'No I'm not, Dave please watch for your cue.' 'Don't worry, I'll be rea-' 'Dave you're on! ' Dave is hurled on stage, an enormous explosion goes off. Sheer panic in his face he shouts.

'What the fuck was that!?'