Smoker and Vergo begin their fight in the SAD Room. At the same time, Sanji, Tashigi, and the G-5 Marines are running through the battle torn B-block when a gas tank explodes, causing Shinokuni to be let in. Caesar Clown, sitting on the second floor of R-block with his subordinates in Vegapunk's old room, instructs that the doors to C and D-blocks be closed, driving everyone to the first floor of R-block where a trap is ready to expose them to Shinokuni. When one of Caesar's subordinates questions the nature of the gas, Caesar then makes a speech to his subordinates, saying that the poisonous gas bomb four years ago was Vegapunk's doing and that Caesar tried to stop him. However, in a flashback it is revealed that Caesar constructed the weapon himself, and when he was told to stop and banished from the science squad, he set it off. While the gates to C and D-blocks are closed, Luffy meets a small dragon who can talk. (thetvdb.com)