First Citizen's would argue that there is more money to be made rescuing at least the cargo of that ship rather than awaiting salvage operations on the seabed.
I outlined 1 possible reason why Jin might have joined AVXL. Another could be the frequently mentioned one that he was thrilled at the data.
Your bizarre analogy of a sinking ship has nothing to do with Jin's possible motivation for joining AVXL. Even if the phase 2b/3 trial isn't deemed insufficient for FDA approval doesn't mean that the ship is sinking. This is an excellent career choice for Jin.