don't forget that this "emergency button" feature is not really useful nowadays, because current memory cards have big size ( 64, 128 Gb ) for a cheap price, the scenario of a loss of important videos is very unlikely,
and more important : the concept of loop recording means that only the most old file is erased when memory card is full, that implies you will have more time to backup the important videos files in your PC,
there is no "emergency" when a big memory card allows you to record 14 hours of videos, if an important event occurs then that means you will have 14 hours before this scene will be deleted ( if you never stop driving, so in reality you will have much more time, probably several weeks if your ride does not last long )