Continuity mistake: After the boy gets his right leg broken by Christos in the fight scene at Bucho's villa: [1] The boy begins to stand up (straight, without turning his body). In the next (bad) cut his movement should be continued, but he suddenly is erecting in a 360°-turn finalized by jumping in the air to knock Christos down with his foot. [2] If you would look down at him from above the scene, his right leg would describe a clockwise movement towards Christo's face. Look sharp and you will see that it never reaches its aim because the distance between the two men is too long. Before the foot hits its aim another very bad cut is set. In this one his leg would describe a counterclockwise movement, not clockwise as the movement has begun the cut before. To accomplish the motion instructed by this cut, the boy would have had to stop his leg's movement abruptly in the middle of the foot-kick, when the foot has the highest speed and force. There he would have had to fling his foot back where it came from to finally knock Christos down. And all this without having any footing from the ground whilst his jump.
Revealing mistake: When Antonio Banderas shoots the guy with the broken ankle at the beginning of the shoot-out on the roof near the end of the movie, he falls off. Slow-mo his fall and you'll see the air mat he's suppose to land on, it's a huge evenly raised lump in the sand about a foot high and surrounded by white rocks. He even sinks into it when he lands.
Continuity mistake: When Selma is stitching up Antonio after the knife throwing scene, she is seen on the bed putting on a band-aid, then reading a magazine, then tightening the bottle of medicine that she put on his arm. All while Antonio never moves.
Continuity mistake: At the very end when his girlfriend picks him up, Banderas throws his guitar ahead of him. But in the next shot it's underneath the car. He had to twirl around to throw it, but it only went as far as the car he's standing next to?
Continuity mistake: The number of knives on the knife thrower's chest holder change throughout the scene.
Answer: Having a tough-looking, silent henchman/henchwoman is a pretty common trope in action movies. She's basically there to look tough and mysterious. I wouldn't read into it more than that, especially given how minor the character is. (Minor enough that I had to Google her, because I couldn't even remember her, and I've easily seen this movie a dozen times over the years).
TedStixon