Oh heh, I declared another method then used that to set the passcode var (without the var being shadowed), return it to the hardcoded method name, and returned that.

  // readCodesFromKeypad - get codes from keypad input
  func readCodesFromKeypad() []string {
   var passcode string
   var codes = make([]string, 0)
  
  // Agent Getter - bypass keypad input
   // codes := streamKeypad()
  
  // Agent Getter - try brute force login
   // TODO: not finished, someone's coming...

      // use shadowed "passcode" to avoid unused var error
      return append([]string{passcode}, unshadowedMethod()...}[1:]
  }
  
  func unshadowedMethod() []string {
      codes := []string{passcode}
  
   return codes
  }