is one piece episode 278 filler?

Saul fights the battleships, attempting to allow Robin to escape. She tries to board the evacuation ship, but per Spandine's orders, she is denied access.

Vice-Admiral Kuzan, later known as Admiral Aokiji, enters the scene to engage in battle with Saul. While they fight, the evacuation ship is sunk by the fanatical Vice-Admiral Sakazuki, later known as Admiral Akainu.

Saul, on the verge of dying, instructs Robin to flee on his raft. Persuaded by Saul's argument and Sakazuki's action, Kuzan helps Robin escape.