The recording is a mish-mash of frequencies. Until Red5 calls, all the calls are on two different apron frequencies. When Red5 calls, he is on 121.9 and is responded to by a male controller. The female controller is working 121.65.
Apron gave the "pushback at your discretion" approval with Westjet directly behind the Sunwing aircraft. Discretion was not used it seems. The view from the Apron tower is limited but...