She watched as he seemed to be thinking, staring off into the dark.

I look over at my mother, who's staring off into space.

Then he goes on sitting and staring off into space.

He stared off into space, with a lost look on his face.

He stared off into the distance for a long moment.

She stood only yards from him, staring off into space.

He turned his back and stared off into the distance.

Particularly the one of you staring off into the middle distance.

For a long moment he stared off into the distance.

For some time he sat there, staring off into nothing.