I didn't think something was right as soon as I noticed the OP said the C was running side-by-side with the ball handler. I guess this is where we introduce that hated buzzword "trail mentality."
If the play was on the sideline, where would the C go to anticipate a play, any play? My first choice would be backing out and getting an open look. We would almost have to see a diagram of the players' position to say where the correct position would have been, but I think the outcome tells us that it wasn't where the C was.
I don't like the L making this call. More than that, I don't like the fact that something went wrong mechanically. The L saved the game and hopefully the C is really thinking about their floor mechanics in a three person game.