When it was cold and snowy in the winter, Sachi had no passionate desire to go outside -- yuck! -- but then spring came and outside became Kitty Mecca. Sachi is a smart and determined little girl. She watched her sister cat, Kitsu, go out through the cat door, so she knew that there was some way to get through that flap of plastic.
She has developed two methodologies.
Number one: While laying on your side, hook the back of the screw holding the wooden knob to the cat flap with sharp claws and pull it upwards. Squirm nose under and slither through.
Number two: Wriggle paw into door mechanism, press down magnetic latch, push on door with head then slide on out.
Last night Kitsu lost her collar with the magnetic key, so now she's the one locked in, dependent upon humans to open the door for her. Ain't that the way it always works?