I have a Sub with 20 drillers, my enemy intercepts the sub with a pirate and 10 drillers.
My sub is destroyed and his pirate returns to the nearest base.
How?

My expectation was he lowers my sub to 10 and they continue to their destination?
Thanks for a response in advance.

He has a general so he destroys 10 drillers and his 10 drillers destroys the other 10.

Thank you, this was hurting my brain.