Final Short Film Idea

So I've come up with this idea for the short film. This guy (protagonist) is at a cafe enjoying coffee and reading a newspaper. A rich snob (antagonist) sits at his table. Protagonist recognizes him as the person his wife is having an affair with but Antagonist doesn't know that Protagonist knows and is here to break it to him. Antagonist had secretly installed a bomb (or whatever it is, I don't know what yet) below the Protagonist's chair before he came and is waiting for the show. He goes to the bathroom to call the Wife to come and witness the show as well. But little did he know, Protagonist already found out and has switched the bomb onto the other chair while he was at the bathroom. The Wife arrives only to witness the rich guy getting blown up or whatever. She decides to go back to Protagonist who sees that she is a player and then pushes her aside.

So how long is this short film? And does it need to have dialogue? Where do we get the dialogue? I think this is too long and complicated so I might come up with another simpler one. XD