It was a little more than midway through the 3rd in the end zone for 18 yards, next play Klecko scored and they tied it up with a 2pt. It sucked but wasn't the swing you remember; the score was 21-13 at the time and it was 2nd and 7 inside the red zone.
As penalties go, the big sequence was late in the 2nd, up 21-3, deep in Colts territory, 3rd and 6, and Brown got an OPI and then Watson illegal motion and 3rd and 6 became 3rd and 21, Brady was sacked, and they went from another score to punting. Colts went down the field and made it 21-6 at the half.