the events, could be this

ON *:TEXT:*:*: check_away $nick $1-
ON *:ACTION:*:*: check_away $nick $1-

alias check_away { 
  if (%AwayControl == ON) && ($me isin $strip($1-)) { 
    notice $nick .:[I am away]:. .:[ Reason: %AwayMSG ]:.
  }
}

no need to use the if ($me != $1-) by the way, its wrong, if you would to use something like this is if ($me !isin $1-), and no halts, look
if your nick its not on $1- and %awaycontrol its not on, it will not be triggered so dont need a check for this

by the way

I'm away bitches

i think this message its kinda offensive for ppl, and some ppl will not like this

u put

unset %AwayMSG, and then unset %AwayNICK,
you could use this unset %Away*

its a simple edit for this