LONGVIEW, Wash. -- A security guard rushed to the aid of a nurse and saved her from being raped Sunday.

Hospital officials said a man walked into the St. John's Medical Center on Sunday afternoon and asked for a doctor.

The man changed into a gown in an exam room. When two nurses entered the room to ask him questions, he turned violent.

Officials said the patient jumped off the bed and attacked a nurse, pinning her against the wall. The man ripped the nurse's shirt and told her he was going to rape her, sources said.

Security guard Joel Reeder said he heard the nurse screaming.

"I come around the corner and all of a sudden I saw this patient on top of our nurse," Reeder said.

Reeder confronted the patient, who backed off the nurse. Reeder then called for back-up and several guards pinned down the patient.

The nurse was shaken up, but she escaped injury.

Reeder said the nurse was grateful he was there.

"She hugged me big time," he said.

Staff at St. John's Medical Center reviewed and improved their security a year ago after someone walked into the emergency room with a gun. Reeder said the hospital has taken the right steps.

"It's an everyday thing," he said. "You don't know what you're going to run into."

Longview police said the man in the attack is being held for a mental evaluation. Officers said he could be charged with attempted rape and assault.

Security Officer Saves Nurse From Being Raped