Does anyone know this book? It starts with a space captain and his ship and crew being attacked by another ship. Eventually the ship was so damaged that they had to board another ship after fleeing (or maybe it just showed up and helped attack).
The inhabitants of the other ship were cat people, humanoids whose eye colors changed with their mood. Green for amusement, black for death, red for anger... There is a female doctor from the destroyed ship that has a brief eye flirtation with one of the cat humanoid officers but they both know a romance would be frowned upon.
The cat humanoids also had a thing where if they got angry they would attack and lose control if they reached a no return point or "killing edge" which got activated a couple times having the humans on board. At one point someone was also "spaced" or they were ejected from the ship aka executed for it (one of the cat people).
Eventually something happens and they are all captured and the cat captain is injured. The cat humanoid captain is injured and the female doctor treats him in the prison cell. At the end the captain finds out that he is a synth of the real captain and hides it I think either because being one is taboo.
I've kept thinking that this book was called Battleship something but cannot find it anywhere.