"I thought time was called..."
My first instinct when you mentioned this scenario was, given that neither player reached 2 game wins (and they hadn't opted to ID the match), the players were (unintentionally) violating tournament procedure. Before time is called, it's not possible to turn in a match result of 1-0-1; the losing player would either have to concede a second game or drop. I decided that the technically correct answer would be to warn each player for Slow Play, as they did not begin their third game in a reasonable amount of time. This would be an extremely pedantic fix, though. While I felt that it was technically correct, and it both (1) educates and encourages the players to fix their error, and (2) accounts for the potential advantage gained by Al, it might not seem an appropriate fix to the players, who will likely see the judge awarding them Slow Plays as simply finding an excuse to penalize them.
Upon reviewing the MTR, though, I'm more inclined to agree with Riki. Section 2.4 says that “A match is considered complete once the result slip is filled out…” So once the players both sign the slip, there aren't any further actions expected of them this match. Warnings for Slow Play would be inappropriate. The players did still violate tournament procedure by not correctly deciding the match, so if an opportunity arises to educate them I'd take it, but there isn't really an applicable fix; the players have agreed to the match result, so it ought to stand as-is.