The Third Alternative Explained

McGinley stared. She wouldn't kill him, surely? His quiet, biddable wife, the devoted mother, she wouldn't be capable, surely?
To save her boys? Yes, she would.
"I'll do whatever you want, Lucy," he heard himself say.
"It's simple, Joshua. I cannot let my boys hang!"
Her gaze roved over the four men on the floor. Doc Morris lay on his back, one leg raised onto an empty chair. The tourniquet he had tied around his thigh did little to staunch the flow of blood.
"We'll kill them all. All, Joshua. Hell, Doc's not going to last, anyway, are you Doc?"