Here's how it would work...

Every two minutes, you will need to cast a vote for someone to die, the person will the most votes will be killed.
If there is a tie, there will be 30 seconds to cast that vote.
You don't have to vote if you don't want to, and you can play it off however you want.

I'm curious to see how it'll play out, but I think it can be a good idea. Game should really not last more than an hour.