At the end when Jessica drives the cart, it's clearly not Angela Lansbury. Her hair and the whole frame is different.
For a former nurse, she's using sloppy technique to fill the syringe.
There are background voices on the lieutenant's end while speaking to Jessica on the phone, but there's no one near him.
Ted refers to "poisonous snakes". "Poisonous" refers to something that kills when swallowed, inhaled, or injected. An animal that produces venom is called "venomous", and Ted should know that.