http://i.imgur.com/FfFc4Yr.png - Drew a diagram of what I tried, ended up dying.
Key is:
X=me
G=guard
B1=Banker1
B2=Banker2
Was I supposed to stand on the X or do you mean in the corner in the very bottom left of the diagram?
Edit: I could stand a tiny bit more "north" on the diagram and not die but hailing/right-clicking Banker1 wouldn't actually do anything, so I moved a tiny bit "south" and died.