To extend the scope from a 25m Depth would require a NEW scope model that was LONG enough to break the surface. The reason It WONT is because the game knows how long the scope is, and how far it can extend it. IF you did indeed have a scope long enough to do the above, you would sadly find out that when it was lowered, you would have nearly 10m of scope sticking out the BOTTOM of you sub. This besides just looking plain silly, would make diving in shallow water a tad difficult.
Welcome aboard, Wardrooms down the gangway second hatch on your left.