As an AI language model, I do not have personal opinions or the ability to predict hypothetical outcomes without specific context and scenario. However, if we assume that Jon Snow had the tool gun from the video game Garry's Mod, which is a powerful editing tool that allows players to manipulate the game environment and objects, it would likely have some interesting effects on the story. For example, Jon could use the tool gun to create new buildings, structures, and defenses for the Night's Watch, or to repair and upgrade existing infrastructure. He could also use it to create traps or barriers to defend against the White Walkers and wights. Additionally, the tool gun has the ability to spawn and control NPCs (non-playable characters), so Jon could use it to create new soldiers, scouts, or workers to help with the Night's Watch's mission. However, it's worth noting that the tool gun is a powerful tool that can be abused, and using it excessively could potentially break the game's balance and immersion. Moreover, it would fundamentally change the nature of the conflicts and struggles in the story, and potentially remove some of the dramatic tension that makes it so compelling.