Depending on how deep she is in sleep, it is possible.

🤨

Plus this is Tatiana Maslany. She's used to it in her roles by now. Might as well add "gets her blood drained in her sleep" as one of the things that are a part of her roles.

Maybe it's some Sci-Fi advanced syringe. Do you feel it being bite by mosquito? Yet it's full of blood on you hands when you clap it to death.

Tbf its just a drop of blood that fits in a mosquito though, lol. But yea, they could surely have applied an anesthetic in the place where the syringe would go. That doesn't seem far fetched.