Try another company, too. My friend that was visiting a few weeks ago had her trip cancelled due to "military exercise," BUT she claimed others that were at the tunnel and observatory did actually go that day. They told her "her time" was cancelled. So check again definitely!

And I mean, yes, I would go to see the Observatory and the Tunnel if you really want to. Just try to book the shortest tour possible for that to save your time. No need for lunch or a tour with a shopping stop.