To inch in any direction would prove instantly fatal.

Seeing Sorrow's face is instantly fatal to almost all living creatures.

Instantly fatal People with high blood pressure are prone to it.

"The problem," I explained, "is this injury to her brain should not have been instantly fatal."

"My thrust was low, not instantly fatal," he said to me now.

The injuries were instantly fatal but not as devastating.

Lower energy requirement, easier to carry: it's not instantly fatal.

Still, it was interesting that the actual cause of death was so perfectly, instantly fatal.

The timing must be perfect; a mistake would be instantly fatal.

Each shot was instantly fatal, and the shots lasted not more than seconds.