Cupola and docking collision?

Structure looks pretty rugged, but "spaceglass" is just that. I
haven't seen a lot of info on the retractable window covers. They
appear to be rather thick, (crushable by design? ) and I'm wondering
as to reason for this?. I do not think that the covers are there for
a pressure seal as well as the design does not look robust enough for
this I haven't seen any protocol s on what needs to be done in case
of a threat to the Cupola? Just imagine anogther Progress or coming
Commercial vehicle impact. When Mir was hit I would imagine a lot of
the energy was absorbed by the solar panel before it hit the pressure
hull, hitting dead on is whole other storyh. Anybody know how fast
the retraction and deploy cycles are?..............Doc