The game tries to behave nicely on many network issues; but the shrine specifically waits indefinitely until the server response so the player can be sure his progress was saved.
Otherwise, it would be far more annoying for the player to find out that the area he worked so hard to complete suddenly is not completed.
If you wish to forfeit the area completion, you can still teleport anywhere via the map (depending the client had that area loaded before the network fail).