Bug or Rule?

Either this is a bug or a rule I didn't know about. :)

In a Live Chess game (http://www.chess.com/livechess/game.html?id=20562586), I had 3:07 remaining, and my opponent was just about out of time. I had a King, s/he had a King and a pawn that was on the g-file, about to promote. I moved, then opponent was going to move, and it drew the game for insufficient material as s/he ran out of time.

Why could I have not run around the middle of the board for the 1 second or so of time that my opponent had left, to win on time? Are you not allowed to win a game on time if you only have the King left? Thanks! :)

Well, good to know. Thanks. :D

Rule: if you don't have enough material left to mate with, you cannot win the game anymore - not even on time. The best you can achieve is a draw.

(well, opponent might resign, but other than that... :-))