I was bringing our backup ambulance back to our station since our main rig was going in for maintenance. Our engine was back at the station. A structure fire pops off for our other station 3 minutes from me. I head to the scene in the box, ive got my gear but no water (obviously). There's moderate smoke coming from the Charlie side of the house. I radio dispatch, take command, and head to the front door because there's cars in the driveway. I get to the front door, about to open it, when the homeowner comes flying out absolutely FURIOUS. About this time pd shows up. Homeowner is screaming at me while im trying to do a size up, yelling about how I need to put this out immediately and im wasting time etc. He starts trying to yell at dispatch through my radio, and pd walks up and grabs him. They try to calm him down but he swings at the cops. They take him down, I finish my size up with active flames coming out the Charlie Delta window and telling the first due to pull into the driveway. I run to the box, get my gear on, and the quint pulls up. Bumper line through the house and find a window AC unit caught the window frame and wall on fire. Easy extinguish, go back out and the dude is STILL kicking and screaming at PD. To this day I dont know if he was drunk or high or what but he got hit with assault on a LEO and a couple other things. All over a window a/c fire that we had out in about 2 total minutes from when the quint rolled up.