Ava could not have unlocked Deborah's iPhone with Face ID.
The message "Your passcode is required when iPhone restarts" is displayed on the phone. Face ID does not work after a phone restart until the passcode is put in. Therefore, because Ava did not know the passcode, a face could not be used to unlock the phone.
In addition, even if this hadn't been after the phone restart, Ava tries to unlock the phone with a passcode several times while looking at it. An iPhone will temporarily turn off Face ID and require a passcode if it doesn't see the expected face five times, yet Ava locked herself out of the phone with passcode guesses, which happens after six times.
The message "Your passcode is required when iPhone restarts" is displayed on the phone. Face ID does not work after a phone restart until the passcode is put in. Therefore, because Ava did not know the passcode, a face could not be used to unlock the phone.
In addition, even if this hadn't been after the phone restart, Ava tries to unlock the phone with a passcode several times while looking at it. An iPhone will temporarily turn off Face ID and require a passcode if it doesn't see the expected face five times, yet Ava locked herself out of the phone with passcode guesses, which happens after six times.