min-dev & `single-frame' AS?

Hi all-

After taking a newbie's look at the examples in

  http://www16.brinkster.com/gazb/ming 

I would greatly appreciate if someone who is proficient at using AS with
ming-dev could explain to those like me me what is the mechanism in the
Flash MX player that allows for placing all actionscript -- both
initialization and action stuff -- in just one frame. When I wrote AS in
ming-0.2a I put the initialization stuff in the first frame, action code
in the other frames, and finally a "gotoandplay(2)" in the last frame.
That made sense to me and now I am confused. 

I am familiar with event-driven code/scripting and I assume the parser
will determine which part of the code is event-related method definition
and which part is not. I imagine the frame is executed in a loop and
event definitions are only read in once; but how would the parser
`know', for example, whether a statement such as X = Y + 1 must be
executed only once or in every loop?

Thanks.

-Laurent