Great design concept and he probably got great marks for the project but it's a warm and fuzzy idea that will be difficult to implement. Their example had a 30 second travel time, the drones would need be based every 500 metres to get that. Where do they house them? unless the collapse is on a footpath outside, where do they land the drone and give adequate directions to the bystander as to where it is? The video was more interested in despatching the drone rather than advising her on the DR ABC basics. It's an immediate conflict, have her commence the basics of DR ABC, or DRS ABC as it is now, or have her leave her dad and run outside? In the video CPR is commenced by a bystander after she runs off.
There's also an issue with the emergency service getting your location via your phone, do you need to turn location services on first? sure the technology is probably there, or almost there for emergency services to crack your location and take it out of your phone immediately, but the civil libertarians will go nuts if the legislation is changed to allow calls to 000/112 to be immediately location monitored. And a lot of ambulance calls are over-exaggerated or false, these little drones would get damaged or stolen in a heart beat, though the would probably put geo fences on them to stop them flying into Rockingham

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Maybe the idea has merit for small scale use on vast mine sites and the like but in populated areas there are many bigger issues to resolve beyond simply attaching a defib machine to a drone.