Actually don't think we would be hard pushed to get rid of Martinez if we win the cup, it'd be case of thanks, but we've decided we need to go in a different direction in terms or managing and coaching so we're terminating your contract with immediate effect.
It really is as simple as that. He would get a payoff and his CV would have two FA Cup wins on it... and we could move on and hopefully quickly improve under a new regime.
If he wins the cup he 100% wont be sacked, even if we finish 17th.