That was one of the dumbest returns on special teams by the Colts that I've ever seen to take the knee. The field position is way less important than giving the Bears a free timeout. Unreal.
Aside from that, they could have passed for free on 1st down without any consequence to the clock since the clock would have 100% stopped at the end of the play anyway and likely caught the Bears off guard. Instead they predictably ran it. Just terrible coaching on the last two plays