Recreate Timer object before starting

Since this can be reused, you can't restart Timers, so create a new one.

sound.py

@@ -51,6 +51,7 @@ def main():
             pg.mixer.Channel(1).play(stageOne)
         elif messagedata == b"stage_2_separation":
             pg.mixer.Channel(2).play(stageTwo)
+            t = Timer(30.0, endMission)
             t.start()
         else:
             print("Unhandled message")