It is strange, but I saw crack shocked unit who was firing at enemy. I think it depends on experience of unit.
When unit is shocked, the best what you can do is to move HQ with red heart nearby.
From observation I think shocked crews don't stay shocked for more than about 60 seconds, but that's bad enough if they're being shot at because most shocked crews won't fire back..
Sometimes I've seen tanks stop dead and auto-cancel their move plots when shocked, but other times I've seen them just carry on rolling like here - (scroll to 'Officer Down') https://www.theblitz.club/message_boards...?tid=39877
As with many things in CM there's a random figure built in, no doubt including shock.
I suppose the computer randomly decides whether a crewman is only scratched and therefore shocked for just the few seconds it takes to dab TCP on it, or whether its a major wound that causes the whole crew to go into immediate severe post-traumatic stress disorder for much longer..