Ruthin Castle bang

Thought you'd like to see what happened Saturday night at Ruthin Castle. I've had to use the live feed and dub my voice recording over the footage. Keep an eye open at the 1min mark as I've drawn a red circle to highlight what I can only caused the bang that scared us. It looks as though the torch that is standing upright on the table is slammed on the table by an invisible force. Seems crazy but 5 mins later I witnessed my own torch which has grooves on it to stop it rolling, moving in front of me!