How does screen find the octal values of a key when one is set in 'bind'?

I am wondering if screen somehow finds the key code via the hardware
or keyboard driver, or if just looks up the value of whatever
character is produced.

Situation:

I have 3 keys next to the media keys that only produce a ^@ NUL
character in cat.
showkey gives me different values for each key though.
I tested with one which produced 144 in showkey.
Converting it to octal gives \220.

So I did

bind \220 exec /usr/bin/mocp -G

It doesn't work.

I'm guessing that screen only looks at the actual character produced
(in this case ^@ NUL) and looks up the number for that, and doesn't
do what I would like - i.e. look at what number the keyboard driver
outputs in the same way that showkey does.

--

The misnaming of fields of study is so common as to lead to what might
be general systems laws.  For example, Frank Harary once suggested the
law that any field that had the word "science" in its name was
guaranteed thereby not to be a science.  He would cite as examples
Military Science, Library Science, Political Science, Homemaking
Science, Social Science, and Computer Science.  Discuss the generality
of this law, and possible reasons for its predictive
power.
    -- Gerald Weinberg, "An Introduction to General Systems
       Thinking."