The minute you killed my 2 engineers was the decline in my game. I thought I was still fighting Rabid & Rosti. My tactics were focused on their style of attacks. I didn't realise you had wiped them out and were so close. You hit my borders very fast, good strategy.
I do love these missions. They develop to be as much about logistics as tactics. Certainly the engineers are key. In fact, this is the first time my engineers didn't spend half the game exhausted. Which probably helped.