I don't understand this question. Who is reading what? What do you mean with model? The bot don't save any conversations. The only stuff the bot is holding in memory are client information like last online time, unique id, nickname and client database id. And of course the permission and server group list for some features. But no chat data will be saved by the bot.
Only the usage of bot commands, like !botinfo, are written to the bot logfile.
Edit: After reading your edit I understand what you mean. You can register some events, like people joining/leaving the server and chat messages to receive them. But I don't know how to handle that with PHP, because you need a permanent telnet connection to the TS3 server.