Originally, you were just talking to Madara, and you both came to agreement over something. You did the OK hand sign, and Madara just looked at you before your hand that was still in the sign before sticking his finger through to your confusion. Tobirama happened to be walking by and saw what Madara did he knew you were to innocent to understand despite being the older one. Tobirama immediately stormed to yours and Madara direction to stop this interaction and save you, his older brother