My understanding is that the feature is not intended to assist in emergencies at all. It is to assist with non-emergency driving conditions and requires the driver to take full control the instant the emergency situation begins to occur.

I recently read a well written article (cannot find the link at the moment) which describes similar problems with aircraft auto pilot situations where the pilot must suddenly take control from the automatic system. Apparently there is a roughly 15 second to one minute time period where the pilot is transitioning from not actually flying the plane to fully understanding what is going on and then figuring out what the pilot must now do. During that transition time neither the pilot nor the automatic system is capable of fully responding to the situation.

There appears to be a similar (perhaps shorter) time period when the non-attentive driver in an assisted driving car must suddenly respond to alerts from the automatic system (or perhaps no alerts at all if the automated system is momentarily fooled or confused) and then figure out what the problem is and what to do about it. That driver control transition time period is likely to be multiple seconds, which may be longer than the time available before something really bad happens.

This problem may turn out to be intractable, which may underlie the expectation from some companies that only fully automated driving will be considered 'safe enough'.

If the car is only capable when the driving is easy and requires the human to suddenly take control when it gets difficult, that is precisely the moments when humans often make errors. Adding the automated mode to human control transition time factor seemingly would exacerbate the human error rate.