Petrie was definitely regretting touching those shiny rocks in the Hidden Cavern. He didn't know at the time what those "rocks" were actually the heads of...
Petrie: "Me knew me shouldn't have looked in the cave..."
Dalek: "EXTERMINATE!!! Zap!"
Petrie: "Ahhh!!!"
Petrie's sibling: "Shut up and fly, Petrie!"