As I said, the debris was likely closer to around ~100km in altitude. Commercial airliners fly around ~10km in altitude. Appearing to be at a similar altitude as the plane and "in front" of it was an optical illusion because the debris was intensely bright, very far away, very high and moving several times faster than a bullet. While we don't have exact data yet, I believe it is
highly likely there was zero chance of that plane ever hitting that debris given their relative positions. It couldn't even if the pilots weren't mistaken about how close the debris was and they had intentionally tried to hit it. The debris was too far, too high and moving at hypersonic speeds (hence the metal being white hot from atmospheric friction).
Starship's flight paths are carefully calculated by SpaceX and the FAA to achieve this exact outcome. In the event of a RUD near orbit, little to no debris will survive reentry. Any that does survive won't reach the surface (or aircraft in flight) until it is far out into the Atlantic Ocean away from land, people, flight paths and shipping lanes. For Starship launches the FAA temporarily closes a large amount of space in the Gulf of Mexico to air and ship traffic because that's where Starship is low and slow enough for debris to be a threat to aircraft. These planes were flying in the Caribbean, where there was no FAA NOTAM closing their airspace because by the time Starship is over the Caribbean, it's in orbit. If there's a RUD over the Caribbean it's already too high and going too fast for debris to be a threat to aircraft or people anywhere near the Carribean. The only "threat" in the Caribbean today was from anyone being distracted by the pretty light show in orbit far above them (that looked deceptively close from some angles).