I have a query regarding the seats in general as I'm not technically minded regarding such matters.
If the seats are fitted with five safety pins and the one in the seat pan was incorrectly fitted, regardless of how, why did the other pins insertion not stop the firing sequence? Is not the removal of the pins the last sequence before engine start as another safety check?
I always thought the idea of the pins was like a weapons safety catch in simple terms in equals no go, out means go out.