This is a fuzzy area. First of all, no, the tip for your regular waiter doesn't get shared with the specialty restaurant.
But, when they first opened the Olympic on the Millie, they were at great pains to tell you that the entire service charge went to tips for the staff there. After that, they raised the service charge, and whether the entire $25 still goes to tips is unclear to me, but some of it surely does. So that means the arrangement is a little different in the specialty restaurant: Tips are provided from the $25 charge, whereas no tips are automatically provided to the regular dining room waiters.
So, the question of additional tipping in the specialties becomes tricky. If the entire $25 goes for tips, it would cover a $125 meal at a land based restaurant at the going rate of 20%. With wine, that's about what a meal for one at the Olympic et al is worth compared to fine dining prices in major metropolitan areas. In fact, it's probably a little heavy, because the wine steward automatically gets his markup on the wine and liquor, just as in the regular dining room. So the proper comparison would actually be a meal without wine or other spirits, which would probably be in the $80-100 range per person.
I'd really like to know how much of the service charge is given to the staff as tips. Then I would calculate and make up any shortfall based on the value of the meal and the service. These servers are the cream of the crop and do an excellent job. They deserve to be rewarded, but accurate information about what's going on would be useful.