Here you see Flo as she reaches the door. You can observe the whole sequence in this AVI movie. Note the sharp clicking sound as Flo approaches the door. This is the electromagnetic coil pulling the latch down. In this zoomed-in version of the same movie you can actually see the latch opening. If Flo is carrying an animal the latch remains in the raised position. She makes a few attempts to push the door open with her nose, then turns around and drags the victim back into the street. As you can see from the movie, there is not much time to spare. The image-recognition algorithm starts at the point in the movie when the mirror on the left becomes dark. It finishes its work just a tiny fraction of a second before Flo reaches the door.

Flo is always free to go in the other direction, nothing prevents the door from opening outwards. For some reason when going outside she always pushes the door open a little bit with her paw, then opens it fully with her nose. She never does that when coming inside. Here is the AVI movie of Flo exiting.