I had a close call this weekend.

I took off in an unobstructed cul-de-sac in front of my house.
Receiving a Low Battery Warning, I piloted it over my driveway towards my house.
Half way there, under a canopy of trees, I received the Critically Low Battery Warning.

The remote control says "Low Battery, Returning home in 10 seconds".

I immediately tried to land, but it would not; instead hovering at about 5 feet.
It seemed confused, not ascending to RTH, and not landing, and moving about.

To prevent a crash into the trees above, I was able to grab the Mavic body.  It then put full power to the props trying to escape, I wasn't sure if I would be able to hold on.

While holding it in one hand, I moved the sticks inward and down to power it off.  Would not work !
I then pressed the pause button, which allowed me to gain control of the Mavic and power it down.

Lesson learned:
Don't fly in obstructed areas with a low battery.
I believe that while in RTH mode, pressing the RTH button will cancel the RTH.

Questions:
Does the ESC button have multiple functions?
Anything I could have done to allow the Mavic to land?

Here is the flight log http://healthydrones.com/main?share=neplpJ

As long as you weren't in a 'CRITICALLY LOW BATTERY' mode and just low battery mode, you can cancel RTH with the button.

From the manual:
"The DJI GO 4 app will display a notice when a low battery warning is triggered.....The user can cancel the RTH procedure by pressing the RTH button on the remote controller."