Can you play 2 games on the same account simultaneously?

I’m asking bc I just played a guy in a bullet game. I wanted a rematch so I went to his profile where it gives you the option to watch their current game. I did, and caught it on the tail end where he lost on time. Maybe 5 seconds max (likely less, I’m being generous here) had passed between the time our game ended and me going to his profile to watch his current game, which he had evidently somehow used all 60 seconds of the clock already on (not counting his opponent’s time, who had like 15 seconds left). I just thought this was odd and wondering if it’s a glitch or a feature?