Slitherine

I think this was answered in the thread, "a complicated situation", but just to confirm...

A unit broken in the assault phase retires as per the outcome moves table. (Note that it explicitly says this in the Firing phase for broken units, but I can't find an equivalent explicit statement in the assault phase section.)

yes that sounds right.
It also probably spells disaster for your opponent as his routers will affect a bunch of his units for shooting