does that even make a difference ? of course it works, it's a matter of initiative.

also to mention your comparing a barrier mystery to a non barrier mystery too.

and in this case barrier of sharky mystery last as long it is up.

I think I know what you mean,

Sharky's barrier mystery does interrupt all Mystery, including stated Uninterruptible Mystery (BT / ST / or not).

No Mystery is usable under Sharky's barrier and I think that IS meant to work that way.

Well.. unless you also want to argue that shouldn't an opponent (second player) Sharky

Ought be able to pull it's Mystery .... while the First Player's Sharky Mystery is already in effect ???