Was flying my MP today and had the app(android) disconnect while I was in point of interest mode.  The mavic kept flying around in a circle, and I still had control via the RC.  I was able to hit the pause button and use the sticks to fly the MP over to me(in a circular pattern) above where I wanted to land, but I could not get out of the POI mode on the controller, so I could not get low enough to land.  I did try the RTH button, and that initiated the landing and bought it down.

Any other way of getting it down?

The only way I was able to get the app to reconnect was by powering down the RC.  Closing the app and relaunching did not work.  I haven't had any app disconnects in about 45 flights untill today, then I got two on the same pack.  Only thing that has changed was this past weekend I got a new battery, and I hooked up my MP to the computer and ran DJI assistant to update the firmware on the battery.  I was not flying with the new battery at this time.  During both disconnects I still had control via the RC.  After the 2nd disconnect the MP seemed abit twitchy, but I was able to land it normally because I was not in a intelligent flight mode.

I did later notice that I had my video cache set at 4 GB and it was almost full, 121 mb left.  I did have it set to clear the cache out automatically though...

Put your Phone in Airplane mode.  I have this issue always happen if my 4g/WiFi/Bluetooth is on. Put in AP mode and never an issue.  A faster way though to get it to reconnect is just unplug from the cable port and plug back in and it comes back.  Seems at least my iPhone 6 interferes with my RC and only way to not have issue is AP mode.  

In my previous 45 flights I have never had to use AP mode.  And I've flown at this particular site probably 30 times now, so I doubt it is anything related to the site or location.

If all you lost was the connection to the phone, you might want to try replacing the short usb cable between the controller to the phone.  The cables that come with the unit are not that durable and have a tendency to fail.  I keep several in my bag.  Don't go to the side port, but get a USB A to USB Micro.  Plug it into the bottom usb port.  
Did you try the pause button on the controller?  That might have broken it out of the Point of interest mode.  If not, the RTH sounds like a good choice also.  The AP mode might help.  I'm like you.  I've flown in the same spot many times, but I still occasionally get a bit of interference.  Give it a shot. And good luck..