As CPR is being performed, there's a shot showing the Silver Doe book on the floor next to a rocking chair. When the camera changes angle to show a closer shot, the book has changed position next to the rocking chair,
At the end of the previous episode, the murder victim was still alive, his hand bloodied and placing a bloodied handprint on the window, as Darby ran off to seek help. In the opening moments of this episode, the victim is already dead, with no blood on him and a different apparent cause of death, prior to Darby's departure.
The injector on the floor is very clearly a adrenaline autoinjector, requiring only one hand to operate. Such devices are used by people who experience anaphylactic reactions and need to inject adrenaline in an emergency. A coroner's daughter who participated in investigations would very likely know not only what the injector is, but that they are pre-filled and non-reusable.
Darby's digital watch is clearly a prop as the screen is completely blank.