Final answer:
The acute accelerated drop in hemoglobin level due to red cells breaking down rapidly occurs during a hemolytic crisis, often associated with conditions such as sickle cell anemia.
Step-by-step explanation:
The acute accelerated drop in the hemoglobin level due to red blood cells breaking down at a faster rate than normal occurs during a hemolytic crisis. This kind of crisis is characterized by the excessive destruction of RBCs, which can be observed in conditions such as sickle cell anemia. In sickle cell anemia, the hemoglobin is unstable causing excessive hemolysis, which results in anemia with symptoms like weakness, shortness of breath, and potential for physical exertion.