You were taking a stroll around GA-metru, taking in the sights of the liquid protodermis reef below you, the domes that they used to purify said liquid protodermis for drinking when you suddenly trip and fall into the reef below, you and presumably the matoran that fell with you swim back to the surface

"What the heck?!"

The dark blue matoran calmed down and introduced herself as vhisola

"Now, why did you trip me into here?"