My first thought was that Tomas set the whole thing up so that he could swoop in and play the savior.

Probably somethign Clint sent in motion. he has no problem breaking the law. He's nothing but a thug who hires other thugs to do his dirty work. He's finally decided to play grandaddy to Shane so I wouldn't be surprised if he set it all in motion, though Tomas is a good guess, too. I just wish someone would go after Rex and beat him up - give him a taste of karma for what he did to Todd.