Stalemate (Uncommon TF2 Control Points Match Ending)

I was stuck on a server by myself for a little bit while in a Control Points match. The system hadn’t registered the fact that I was entirely alone with no one on the opposing team. So I was able to mess around for a while and I ended up getting this round ending I had never seen before. I never heard the voicelines or the sound effects for it either. Who knew you could get a stalemate in TF2?