So...Reiner and Bertolt have been held hostage for the past two weeks or so after they were kidnapped. They were kept unconscious and when they did wake, they were pretty well beaten down.
Just after Reiner's note to the Survey Corps, reports of the Armored Titan appearing briefly started spreading. He only could shift for a few seconds before being recaptured.
Feel free to have characters react to this as they were being held somewhere in the interior so panic most likely would have ensued!