Just a thought I had, like what can a ten year old do(besides mass murder & accidents) that messes up their life so badly that it is unrecoverable?
It has to be something that is self inflicted and not something that is the cause of others around them.
Any significant injury that results in paralysis would be a potential candidate. These become possible as soon as you become old enough to climb things like trees.
I can do you one better: decide to explore near that baby gate that got left open.