@Sihyung a little bit unnatural, but people would understand you if you said this. You can change it like "While she was in the hospital she just wanted to go home." or "When(ever) she was in the hospital she wanted to go home." In English it's usually ordered like while x happens then y happens. Example: "While I hated to go to work, I needed to make money." "While you're on vacation you'll need someone to look after your pets."