A few hours after terrorists attacked the World Trade Center and the Pentagon, the U.S. Army Reserve called Capt. Ellen Beauchaine of Waltham to ask whether she could be ready to leave Maine within 24 hours.

She immediately left her nursing job in an Eastern Maine Medical Center operating room in Bangor and went home and packed.

She called her daughter and they cried together.

She was anxious and fearful and deeply emotional as she packed her duffel bag and got her gun.

She jumped every time the phone rang.

She relied on her husband, Robert, who fought for the Navy in Vietnam, to tell her she would be OK. To reassure her she could do it. To remind her that she had been training for 20 years for what now seemed so imminent.

Any hour, any day she would get that second call and leave for some unknown place where temporary hospitals needed erecting, and casualties – the fortunate ones – needed doctors and operating room nurses.

Some 21,000 hours and counting after packing her Army bag, Beauchaine is still waiting for that second call.

She knows it will come.

“Inevitable,” Beauchaine, a nurse, registered Maine guide, grandmother and officer in charge of the 309th Combat Support Hospital division, headquartered in Bangor, said in a recent interview.

“It was a dark time,” Beauchaine said of the months after the horrifying Sept. 11, 2001, terror attacks, when the waiting was excruciating and her nerves were taut from stress and worry.

“It was bad. It was probably driving me crazy. I was exhausted from worrying,” she said. “I prayed a lot about it. I was crying a lot. My husband and I were talking a lot.

“It was just a very difficult time,” she said, frowning from the memories.

“Wonderful, supportive” friends and colleagues at EMMC and in the 309th, and her husband’s abiding support and empathy, helped her through the darkness, she said.

But in the end, it was her Christian faith that saved her and helped her overcome her fear of leaving the safety of her home and family to go to war, the nurse said.

“I finally had to get down on my knees” and pray, she said. “I was so obsessed. Everything was completely shaded by this.”

Some members of the 309th already have been called up and are serving in Iraq. They are her friends and comrades, and as she keeps her vigil, they are always on her mind and in her prayers.

“It’s difficult just to be waiting. Some of my friends are there and my heart is there with them,” she said. “I’m ready to go. I want to go.”

As soon as she gets the call.