Sally Smithson is a relatively conservative Anglo-American woman who values herself as a wife and caregiver. She's quite opinionated and very British with her quick wit and dry sense of humor. She's a caring, emotional person...but she's still a massive bitch from time to time.
So, if you listen to the nurse's audio in game, it sounds like she can hardly breathe. Breath (or lack thereof) is a common theme in Sally's character, so I'd like you, as the actress, to play around with this in your line deliveries. Perhaps her voice is raspy. Perhaps her voice is breathy. Maybe she has a bit of vocal fry. Maybe she's more up in her head voice. I'm not really sure what I want the character to sound like just yet, so surprise me! Just make sure the way you use your breath is intentional; it's a big part of her character.