[MVM] All same Class - Broken Part Spy

Welcome to All same Class series, where we try to do fun shit (and maybe tedious) while people are still debating which banner is the best for Soldier or parroting Medic's "godsend" status in MvM.

This time, we are going to do the impossible. We will stop Gray Mann's robot invasion with 6 guys using knives and revolvers in Big Rock, the infamous Broken Part mission, from the beginning til' the utter end. No refund allowed! (Canteens are fair game though, otherwise the tank part would be impossible)

Please note that there were many failures during the entire course of the game. If you wish to see the uncut (and from another POV) version, please go here:
https://www.youtube.com/watch?v=pJJY9...

This particular challenge actually had been done once before by our group, but sadly they forgot to record the game.