The real answer is because the Bears had all three timeouts left, so they wouldn't need much time at all to drive down and score. All it would have taken was a couple of incompletions, a sack/penalty, etc., and the Bears get the ball back with over a minute and multiple timeouts left.
If the Bears had only one or zero timeouts left, they likely would have called timeout there. It's about how much time the Bears would need to score given how many timeouts they have left.