Where was Chazou when Tenshinhan was in the desert? And why was Tien alive? And was Korin alive?

[Warmmedown]

When Tien was in the desert about to be made into dessert, where was Chazou? Was he already dead? How tf was Tien not dead after Super Buu killed everyone not on the Kami's lookout? Also was Korin alive still?