I assume that the author has been on planes enough to think about this and make a website with a simulation.
It seems fairly realistic to me. People in rows toward the front step into the aisle as soon as possible to gather their carry-ons. This blocks everyone rearward that already has their belongings and is in the aisle from deplaning.
Unloaders will yield to a non-zero average of waiting passengers. Unloading passengers in fore rows can predict, time, and exploit gaps in passing back row passengers such that they can unload without causing slowdown (in this way full and flush in non-optimal).
The simulation currently encodes an average 2 second gap between passengers in the deplaning aisle - in theory you could shoot in when a passenger with a longer minbuffer is near you. This can be done so long as it does not cause accordion-style congestion in the aisle.
It seems fairly realistic to me. People in rows toward the front step into the aisle as soon as possible to gather their carry-ons. This blocks everyone rearward that already has their belongings and is in the aisle from deplaning.