break one's neck

"One might break one's neck if one were careless," he continued in a musing tone.

It is easy to mount the ladder, but the question is not to break one's neck.'

On the way home, when the newly-created angel is hastening heavenward, one may break one's neck.

He would relieve his feelings by undertaking some desperate feat—thank Heaven, it was always easy to break one’s neck.

Since night had come it was easy to break one's neck.