so did El Mariachi betray Sands in the end cuz.........

Wasn't EL Mariachi SUPPOSED to wait for General Marquez and Barillo to kill the President and then take out Marquez while Eva Mendes's character or whoever was to arrest Barillo? That's what Sands told him but in the end El Mariachi decides to save the President, thus breaking his agreement with Sands. According to Sands this was supposed to be a "healthy" coup de etat with the President ( that so delicious slice of pork as Sands calls it) "sliced" out and the corrupt General Marquez dead and Cartel leader Barillo arrested.
I'm a little lost here......
Also, does anyone hear think that Sands or the CIA would hunt down El Mariachi since he didn't let the President die and wouldn't Sands get in trouble with the CIA since one of their objectives ( President killed) not being accomplished?