I know I'm not the only one that's had the app crash in the middle of a flight but one nice thing about it is the remote still has control of the drone.
While flying my P3 4K aroung a wooded area and out of sight mostly due to the trees blocking the view the app crashed.
I already was prepared for such an incident because I've had it happen a few times before this so here's what I did.
as soon as the app crashed I released the controls so it would hover then I raised it's altitude to a point that I figured would be in sight from the obsticles around me
I grabbed my binoculars and located the drone and was able to get it turned back in my direction and flew it back to where I was.
Just thought I would share this info case some one has the same issue they can do this rather panic.
He said the button on the remote, not the screen, it will still work. But if it was in amongst trees, that would not be a good idea. What the OP did was probably the best course of action in the circumstances.