HN - I do not see it so clearly - the water, which is providing the retardation force is 'retarding' the gear also and may balance the 'inertia' of that. Only if you slowed the rest of the a/c leaving the gear unaffected by entry into the water would what you say be a 'definite'. I am sure the only certain way to know is to look at the various bits of the assembly in terms of what goes where on a 'normal' extension and what has sheared from what in line with CliveL's post. We could well just be looking a slow 'gravity' drop from a broken airframe as it made its way down 3900m.