活动中心

活 = 氵 + 舌 : Helga Horse joined the traditional water bottle challenge and empties a bottle of water over herself in the observatory's kitchen. To raise the difficulty level, she only uses her tongue to hold the bottle.

动 = 云 + 力 : Doggy Dog notices a lot of smoke when he enters engine's bathroom. Instead of thinking long, he acts quickly and moves to push the fire alarm button.

中 = 丨 + 口 : Mnemonic symbol: a dart board, because you always try to hit the center.

Julian Giant Squid (zhu-) is throwing dinosaur bones (丨) as darts on a dart board in front of the engine ((e)ng1). To make it a bit more difficult he's throwing mandarins (口) into the air as well and skewers them up right in the center (中 is a mandarin skewered on a dinosaur bone) in mid flight with the dinosaur bones. He's still able to consistently hit the center (中) of the dart board.

心 = 乚 + 丶 : Marie Curie (xi) uses a shovel (乚) to dig a hole in front of the encampment ((e)n1). She wants to bury her heart (心). To the side are three petal leaves (丶), with which she wants to cover it afterwards.