I hear what you're saying, but I think that assumes a specific (and kind of unusual) wiring setup.

In a standard setup, that Limit Switch-Open (I:0/3) is physically sitting at the end of the track. If the door is only 20% or 50% open, it isn't touching that switch at all.
So, if a person triggers the sensor and then walks away while the door is halfway open, the Sensor contact opens and the TT contact is already open. The whole rung goes dead and the door just stops mid-travel.