In a way, they are hiding in the open, which is a tool of survival for these helpless kids.

Interestingly and sadly, abused children often manifest these freezing
limbic behaviors. In the presence of an abusive parent or adult, their
arms will go dormant at their sides and they avoid eye contact as though
that helps them not to be seen. In a way, they are hiding in the open,
which is a tool of survival for these helpless kids

In the paragraph above the last sentence seems contradictory. It says they are hiding in the open which means that this is not an effective strategy. On the other hand it says that is a tool for survival which means that that strategy is an effective one. Because tools are used to facilitate things otherwise it would be denoted as a failed thing not designated as a "tool". Also it says it is a tool for survival that means it is a thing used successfully for survival. So I am confused actually.

Please help.