You're in denial.Night guy was Guy ultimate attack. It was faster and more powerful than Evening elephant. The Anime failed to portray Guy's movement when using Night Guy. For instance, the recent Dragon Ball Super episode showed the battle between Beerus and SSJ3 Goku. Normally, SSJ3 Goku punches and movement are lightspeed if not more. However the Anime failed to depicts any instantaneous movement, Beerus was basically evading Goku's assaults while having a conversation with him. Same situation can be applied to why Guy movement wasn't actually instantaneous when the Anime was released. The Anime editors just want us to follow the scene without being confused.
Ok Both of you should keep on staying in denial!
Gai was not moving at 186,282 miles per second.