screen indicators passing throgh loops

Hi there.

I have the following code (greatly simplified).

/free
exfmt screen1;
dow not I.Exit;
// read some stuff, do some stuff
exfmt screen2;
dow not I.Exit and not I.Cancel;
// read some stuff, do some stuff
exfmt screen2;
endDo;
exfmt screen1;
endDo;
*inlr = *on;
/end-free

"I" it's a DS holding the indicators being set by the command keys at the
interactive stage (03 and 12 respectively).

My plan was: if you press F12 on screen2, you go back to screen1. But if you
press F3 on either screen you go out of the program directly.

The sucker only works half through. I can exit the program from
screen1 pressing
F3, and I can go back from screen2 pressing F12. But attempting to Exit the
program from screen2 gets the same effect than pressing F12 (I get back to
screen1).

Is the I.Exit indicator reseted by the sole action of reading it in the
innermost 'dow'? Shouldn't it be still on when the program gets back to the
outermost loop (and hence skipping it altogether?). On my mind this seems to
be the cleaner path. It's rather frustrating that it doesn't work.

Thx and regards, and excuse the lameness for the question. I could have
written a workaround for this, but I'd like to understand what's going on.

I.-