Great episode! I wonder if maybe the Mallers shot down the helicopter? Scratch could have noticed and assumed Michael and Pegs. That could be what triggers the Fort to go investigate and find the Colony right where we left off at the end of Chapter 32. Best bet though is the Soldier turned and took out everyone on board and crashed near Boulder, and with defense relaxed at Boulder due to winter and possibly a slowdown in zombie activity, the Zombie leftovers from the crash make their way to Boulder and that is where we get "Red Winter".