Dangerous Encounters--1st kind: questions and possible goof?

[pjshimmer]

Hopefully someone has the details committed to memory :p

Is this a goof? In the parking lot scene, one of the 4 guys evaded death by throwing cash in the air. It should have been cash in local dollars, since they had just exchanged their $1 million yen bills for 30% cash. Later, when Uncle Hak's man brought out the bill, it is mysteriously in the form of $1 million yen (when it should have been cash), which prompted the Westerner to wipe them out. Now, how come this man picked up yen bills?

Question 1: why did 2 of the 3 guys poison their tall friend?

question 2: what is the thing that was dropped from top of a building to a lady's umbrella?