While Roman is lying on the hospital bed, behind him is the biometric screen, showing pulse, breathing rate, etc. However, Roman sits up, and then gets up and walks away from the hospital bed, clearly not connected to the biometrics. Even after Roman walks out of frame, the biometrics continue to show active data.
While Avery & Roman are having a snowball fight on the street, you can see there is no snow on the cross street in the background.
When Roman calls Avery to invite her to his parents party , you can clearly see Averys phone screen, there is just a standard screen saver not the usual screen to suggest you're on a call.