We had such a case with a member of our forum.
Her linnie escaped through the cat's door and was never seen again although it was partly clipped.
That is sad, sometimes these birds are too smart for their own good.
I have a feeling the owner of this bird knows exactly what her bird can and can't do and isn't worried he will get away while she films him.
It is concerning to know your bird knows it can get outside and has access to a door that might be open while you are elsewhere in the house. It only takes a minute for a bird to make a get away.
Also, it only takes a minute for a sneaky interested neighborhood cat or dog to run in an open doggy door and chase after a pet bird as well.