Continuity mistake: The blood stain on Cooke's shirt differs depending on the angle focusing him. (00:47:35)
Continuity mistake: At the mall, when Matrix tells the girl to walk behind the baddie, he stands by a column and a man walks behind him. In the close-up he disappears and is replaced by two guys. (00:33:10)
Continuity mistake: When Matrix and Cooke fight at the motel, the number and shape of broken glass-tiles on the wall keeps increasing / decreasing randomly in different shots. (00:46:25)
Continuity mistake: The yellow Porsche crashes on some dusty trail with no yellow lines painted on its floor. When Matrix walks towards the car, it's now by a yellow line on a paved road. (00:40:15)
Continuity mistake: When Matrix shakes the phone booth at the mall, the hole on the glass increases / decreases randomly. (00:36:00)
Continuity mistake: During the fight at the end of the movie between Matrix and Bennett when Bennett calls Matrix a "dead man" and he responds with "Bullshit" you see him come off the wall with his left hand. He is throwing a left hook, but in the very next shot when the punch comes in contact with Bennett his fist is going from right to left in a backfist motion, rather than a left to right hook. (01:23:45)
Continuity mistake: Right when the fight between Matrix and Bennett begins, the Uzi submachine gun vanishes from Bennett's right shoulder (it was on a strap). Then suddenly at the end of the fight (after the fell down over the railing and to the next level down, the Uzi reappears when Bennett picks it up and attempts to shoot Matrix. Bennett lost it on the upper level nowhere near the railing, and it somehow appeared on the lower level away from the railing.
Continuity mistake: While eating sandwiches, Matrix's daughter says, "You don't wanna know" as she reaches for a napkin. A frame later, from a different angle, her hands are empty as they reach for the napkin. (00:08:20)
Continuity mistake: During the machine gun scene at the en Matrix has a belt fed M60 machine gun. When the fight starts, he has plenty of bullets. A few seconds later he has about 20 cm length of the bullet belt left. Scene switch - and he has more bullets. This switch between low and high ammo a few times. (01:16:15)
Continuity mistake: When the thug meets Cindy by the public phones, him and the people behind her (lady in pink and man in green) drastically change positions between the first and second shot. (00:25:50)
Continuity mistake: When the military guy leaves Matrix's house, the chopper's shadow points in a 12 o'clock direction. A frame later it's pointing to 3 o'clock. (00:11:25)
Answer: Possibly so any surviving enemies they encountered on previous missions and or tours of duty couldn't hunt them down and kill them for revenge.