Today's Chinese Lesson:

"Wo bu yao zai ni de ji cheng che li si diao le"
"I don't want to die in your taxi."

Of course, failing that, there are lots of other things you could
do to communicate this message, and be understood without any
language at all. Diving to the floorboard would work, or very pointedly
fastening your seatbelt while giving him an evil look.