instead of making it say that lame stuff why not just have it set them as back if they talk.
also no reason to set vars

alias a { 
  .away $iif($1-,$v1,Gone) 
  amsg I'm now away from IRC for the following reason: $iif($1-,$v1,Gone) 
  nick $+($me,[AFK])
}
alias b { 
  .away 
  nick $remove($me,[AFK])
  amsg I'm now back from: $awaymsg [This horrifying mess took me $duration($awaytime) to complete]  
}
on *:input:*: { 
  if ($away) { b }
}