At that point the clock was ticking on 2nd down with less than 30 seconds to play. If they had ran the ball again with Lynch at the 1 yard line and got stopped, Seattle could call a timeout and stop the clock at around 22 seconds. Then Seattle would either try again on 3rd down and quickly get up for one last snap on 4th down if stopped, or try for a pass play for a TD or incomplete to stop the clock again on 3rd down and then take your best play on 4th down with the clock stopped for a TD attempt. At that point, let's say Seattle did score a touchdown on 3rd or 4th down, there would have only been roughly 10-15 seconds left in the game, leaving only one chance for a hail mary with roughly 7-10 seconds left depending on the kickoff.