Nice work, some small (should be fixable) annoyances though.
If you fire 2 bullets out of your sawn off then change weapons 10 seconds later (or any amount of time) you will still freeze. If you fire 2-shots then use your other weapon (while not taking advantage of the 2-shot rapid fire) then you will still also freeze, both are related to the same thing.
I think the issue could be resolved by moving the freeze trigger to when they shoot again, then adding a time check i.e. only freeze when they switch from and to sawnoff within x milliseconds. Yes, it probably wouldn't prevent 2-shot for laggers (shot fired sent before trigger and freeze animation*) but it'd still kill the advantages a player tried to gain from using the bug.
I'm not sure if this is with your updated version. I'm not sure if dugi put your older or newer version on the main server for testing.
(*You could try a return 0 to desync the 2-shot fired for other players. I'm not sure if that will cause some sort of desynced aftermath though.)