diff --git a/matrix_pygmalion_bot/core.py b/matrix_pygmalion_bot/core.py
index f39bc2c..253f897 100644
--- a/matrix_pygmalion_bot/core.py
+++ b/matrix_pygmalion_bot/core.py
@@ -151,6 +151,7 @@ class Callbacks(object):
                 self.bot.negative_prompt = negative_prompt
             else:
                 self.bot.negative_prompt = None
+            return
         elif event.body.startswith('!begin'):
             self.bot.chat_history.room(room.display_name).clear()
             self.bot.room_config[room.room_id]["tick"] = 0