I was Watching The Host (2013), Melanie who is in the head of Wanderer, Actually Doctor skipped the aid of her brother Jamie, so Wanderer got doubt tries to enter into doctor room.
But Melanie resists her, why so?
She didn't want her to see and know what they're doing to "her people".
That's what happened when she entered:
Wanderer enters the community's medical facility and discovers that Doc has been experimenting with ways to remove Souls and allow the host's mind to regain control, resulting in the deaths of many Souls and Hosts from his failed experiments. Wikipedia