I Will Follow You Into the Dark
![](https://image.tmdb.org/t/p/original/7V8UzYNLEzgYc0Mh3DDRfyjpQVI.jpg)
- Runtime
- 43m
- Air Date
- Aired Mar 12, 2009
Derek decides to quit after learning that more of his patients have died than survived; Izzie's interns make an unsettling discovery about "Patient X."
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I Will Follow You Into the Dark
Derek decides to quit after learning that more of his patients have died than survived; Izzie's interns make an unsettling discovery about "Patient X."