I sat on/served as Recorder (essentially board executive assistant to Board President) on several lateral transfer/redesignation boards for Navy officers wishing to switch from one warfare community to another.
All the respective community boards meet at the same time to review those who want to leave a community and those who want to get in. There are always more applicants than there are slots. First pass through the stacks of application packages and fitness report records, eliminate those who were non-performers, middle of the pack and likely non-promotes, of those who wanted to get into your community. Second pass, eliminate those whose applications were not in required format, or other eligibility issues. Third pass, eliminate those requesting to leave the community who would not be allowed to go elsewhere because of under-staffing in a specific year group - needs of the Navy prevail. Then, rack and stack remaining records, from top performers down to the lesser top performers. If you only had 3 slots available in a given year group, you wanted promotable, pack-plus performers from other communities to fill those slots. Then the horse-trading commences among the communities, with proven performers as the only desirable trades. Record comparisons go w-a-a-a-y back. Someone who got bounced from a school pipeline, when clearly they had better potential - red flag.
Top, pack-plus performance almost always gives an officer maximum leverage to get what they want. Non-performing officers, even those on a campaign to escape a specific warfare track, put themselves in peril of being fodder for a "hot fill." The blast goes out from Placement, who looks after staffing for commands, to Detailing, who works with individual officers. Needed: any 0-2/3, any warfare specialty, for immediate must-fill assignment to staff watch officer, duty station z, for a period of two years, unaccompanied. There are many, many not-so-fun jobs in not-so-fun places, that the officer who has dropped to pack-minus and essentially becomes non-promotable, can find unexpected orders arriving for. Worst case, but it happens. Very hard to job hunt when OCONUS in a warm body job.
Understanding the sub draft concern, I counsel performing well and being honest about desires, respectful of subs, in interviews when asked. The admiral's duty is to look after the needs of the Navy, same theory as a sub skipper under attack on the surface who makes the decision to dive and save his/her sub and crew to fight another day, but who may have to abandon wounded topside. Drastic comparison, but admirals get to where they are by understanding and executing to the big picture of getting sufficient top performers into their community to maintain operational excellence. That said, it won't be news to an interviewing officer that some candidates are less than thrilled and perhaps will not make the best sub officer. No one wants a bitter, resentful officer leading enlisted troops.
Don't let yourself down. The risk of doing something you don't want is part of the deal. If it happens, be the best you can be, and other doors will open. Don't be less if you can do more. You will likely live 80-something years. If you have to devote a sliver to something not your first choice, do it with your best self.