The ending scene kinda ruin it

No trial for him ... too much classified info would come to light.

I disagree. He got what he deserved.

It was a terrible ending because it had the heroine become the very lawless murderer she was fighting against over the prior hour and a half. And it didn’t help that her new boss, John Malkovich (who is now almost typecast for playing morally corrupt characters), picks her up in a limo 30 seconds after she murders Mercer and they smile and end the movie with dialogue about getting coffee and pastries.