/debug is meant to monitor any data exchange between mirc and the server you're connected to. You need to open the window, do a /whois (or whatever else) and watch the window to know the order of the parameters, and the numeric belongs to each raw.
Anyhow, only /whois tells what channels the user is on, /who doesn't. If you wanted to make a bad channel kicker, it would be easier (and faster) if the bot sits in the bad channel (so that it can see who joins), and do a simple "if ($nick ison #badchan)" comparison when someone joins your channel.
