The dialogue on the recording Derrick (Michael Ealy) plays for Detective Quinlan (Hilary Swank) on his phone obviously does not match the conversation they had only a few minutes before entering the elevator.
When Quinlan fires her pump shotgun, one time she doesn't use the pump when walking down the hall. When in the kitchen, she fires two shots simultaneously without pumping to reload.
Fire or ambulance would not respond to an active shooting until police have 'staged' or cleared the area to protect EMS responders.
When Derrick initially searches Val on the internet, the text in one of the articles contains the common grammatical it's/its error: "To no one's surprise, Detective Valerie Quinlan was it's recipient, celebrating her groundbreaking investigation that cracked four cold cases from 2010."
When it's obvious that Tyler's gun has blanks, it's off that Quinlan orders him to drop the weapon.
Around 1:05:45, the TV news report misspells Tracie's name as "Tracy."