They were going to try to catch the Bears with 12 men on the field. But the Colts should go for it here. Possessions are scarce, and the Colts have a good chance of picking up a 4th and 1. If you don't get it, you don't get it. But you can't meekly punt the ball away down 2 scores. Sure go ahead. GO FOR IT. That's fine. The math says to go for it every single time in that situation. 1st quarter, 4th quarter, it doesn't matter. Stupid play call though. If your math includes the "Bears offense sucks" factor, then may I suggest you recalculate? Nah, the average NFL play goes 2.5 yards. Any time you only have to get one yard on a play, it's worth it unless you're pinned back on your own 1/3 of the field. At midfield, the chances of gaining 1 yard outweigh the benefit of the average punt distance (~30 yds) from that point.