Heihachi followed as Seijuro expected, and in the moment it took Heihachi to enter Sage Mode Seijuro made a single one-handed seal and awaited the Sage's entry. He was either very foolish or very confident in himself. Once the old man locked eyes with Seijuro, his eyebrows narrowed and a sly smirk crept across his face. His eyes bounced up and down the Sage, and back to his eyes. The legends were true, he was a man built like a house from the ground up but had the elegance of water. The way he carried himself... yes, this reaffirmed Seijuro's choice to seek him out. However, he wasn't sold on the old man just yet... 

[i]CRACK![/i] Seijuro disappeared from his spot in an instant leaving cracks in the ground in his wake, a white-cloaked blur rocketing at the Jellyfish Sage with murderous intent. The hand seal Seijuro used prior would cause Heihachi to react a fraction of a second later later to his movements, as the moment Heihachi walked into the warehouse his focus was on Seijuro, their eyes had met, allowing his Magen: Shiyoutenshindo to take effect. When paired with the speed of his Shinsoku it made it so only the Shinobi with true analytical skill and optimal reaction timing could dodge. 

By the time Seijuro was upon the Sage his Ozorou no Tantou had been summoned to his hands, each of them coming across Seijuro's body in an X-shaped attac on Heihachi's torso. His eyes remained locked on Heihachi's, even in the midst of an attack he was gazing into the thoughts of his prey. But why was Seijuro doing this? Attacking a high-ranking rebel was serious and he was spelling out his own death if he was really about to cause a scene in the middle of Konoha even if it was in some abandoned warehouse. Yet Seijuro attacked without hesitation or explanation. It was all part of his plan, after all.