"A gov. research group housed in Cleburne's Memorial Hospital ensured it
military protection, keeping it operational long after other medial facilities
failed."
This level is really straight-forward. You're in a hospital the entire time,
and all you need to do is use your compass and the red arrow to traverse
through its halls. Kill the zombies as you see them, or you can choose to sneak
by them if that's easier or faster for you.
You'll find Noah. He was the guy with the gunshot wound from the diner. Scout
is in the morgue looking for medical supplies to help him. Meanwhile, you are
looking for medical supplies to help Merle. As you follow the red arrow, you
will be subjected to a zombie bursting through a door and surprising you with
a QTE.
In another instance, you'll walk by double doors that are boarded up. Sprint
by them and keep following the red arrow. The zombies will break through that
door and come after you. Keep running through the halls and then as you move
through smokey areas, the floor will collapse underneath Daryl's feet.
When you regain control, keep moving through the hospital. The red arrows will
lead you to a doctor that has Noah set up in an experiment. You can choose to
side with the doctor or choose to save Noah. Either way, you'll get the medical
supplies. If you save Noah, you'll have to save him from zombies and then talk
to him to get the supplies.
The red arrows will then lead you to the parking garage exit. I recommend
running by the walkers for the duration of this level to avoid taking damage.
Source: http://www.cheatmasters.com/blog/2013/03/21/the-walking-dead-survival-instinct-guide/#ixzz2pbErDosW