In this youtube video about a water cooled desktop PC build log the author uses glass tubing to route the water around the system. Around 4:08, when the first tube break/cut is shown, the author pours a small amount of water on the tube after scoring it. I've heard of "shocking" glass with hot water when cutting it, but the author does not mention that the water is hot. Further the author seems to use the same cup of water over some period of time, so it doesn't seem to be hot.
Why pour water on glass after scoring it to break it?