Scott and four companions died on the way out.

De Long and 12 companions died of starvation; the others reached safety.

He had been one of a pair, but his companion subsequently died.

His companion, a young woman who was not immediately identified, also died of a head wound at the scene.

How many times this day must he stand helpless as companions died?

They did not realize the nature of the visitor, or know that their companion had died.

Unfortunately, her three exotic companions and the human pilot died.

If they had, she and her companions would probably have died.

The companions, one hopes, died of natural causes, though this cannot always be assumed.

Having seen so many companions leave or die, the Doctor built a companion who would always stay with him.