Hi Yael,
So far I cannot see why your app stops when you build an .apk
I do see a whole lot of code that I do not understand.
I reworked your .Timer routine like this:

The procedures I built with moving your blocks look like this:

WHY? What is supposed to happen??
There are 32 statements like this:

What is the purpose of this?? Does it ever happen that global Multi = 0??
Important question: does your app work as expected when you run it in the companion??
If no, please make it work in the Companion first!
If yes, please explain better what the app should do. And in that case I will look further (Maybe tomorrow).
Cheers, Ghica.