is bleach episode 288 filler?

Ichigo and Captain Retsu Unohana are standing in front of Captain Mayuri Kurotsuchi's Garganta. The captain spares them the lengthy explanations and simply states if they make it to the other side they'll be in the Human World.

Mayuri adds a warning though, saying one false step inside the Garganta could cause them to lose their way in the uncharted space between Hueco Mundo and the Human world from which they will never return. Ichigo compares the situation to the time Kisuke Urahara sent Uryū Ishida, Yasutora Sado, and himself into Hueco Mundo to rescue Orihime Inoue.

He remarks that Mayuri must have been Urahara's disciple at one point, as the two of them are quite similar.