Kara mentions flying fast and turning back time... something that Superman did in the original Superman movie starring Christopher Reeve.
Chyler Leigh (Alex Danvers) was so scared to get in the water tank when filming her scene that she was allowed to call her husband and kids to tell them she loves them and that she'll be home soon, meanwhile, the crew was telling her that it's ok, they're not actually going to kill her.
Just before Peter Thompson (played by Gregg Henry) is interviewed in his holding cell a shot from outside the prison reveals its location as "San Quintin State Penitentiary" located in Marin County CA.
Rick Malverne's name echoes that of Dick Malverne, a character from 1960's era Supergirl comic book stories who served as a companion and potential love interest for Linda Danvers.