"My friend and I then realized we could probably help," he wrote in a Reddit videos thread. And help they did - kicking in doors to search for people and saving a frightened corgi from the blaze - all caught on camera.
"What you don't see in the video is that the fire started to get out of control afterwards and the whole upstairs filled with smoke. That corgi would have died," Spencer wrote.
Unfortunately, the corgi ran away terrified, and his owner is still looking for him - but happy that he's alive and misplaced. Spencer and his friend saved a total of three dogs from the building.
Helpful Redditors were broadly on board with the heroics, but offered advice for any other would-be heroes, which included closing doors behind you to limit ventilation to the fire, and the be more careful checking the heat around the door frame first.
Other advice included to use a strong kick to the area near the lock, and not a shoulder - with Colonel Whiskers confessing hid friend did, in fact, injure himself doing this.
"I used both feet with my back on the railing. Dumb idea but it worked. The one with the deadbolt later on in the video seemed really strong but the dude in the orange shirt barrelled through it easily."
Now, Spencer's monetised the video to generate some spare change from adverts - which he says he will donate to his city's fire department.
Local media reports claimed the fire, which partially collapsed the roof of the complex, had been started by a lightning strike.