Bull Rush direction?

[Mr. Microscope]

I always assumed that the movement from a bull rush must be in the same direction as the charge, but an adventure I'm running has me questioning that.
The encounter takes place on a bridge. PC's from the middle, monster on the end. The text says that the monster charges the PC's attempts bull rush them off the bridge, but that would require the PC to fly off the bridge in a diagonal.

Can you make a charge attack/bull rush and push an opponent on a diagonal tangent from the charge direction?

Thank you!

[Pink Dragon]

Page 199 Core Rule Book:
A bull rush attempts to push an opponent straight back without doing any harm.

In a normal movement where the bull rushing character can change direction at any time, I would say that pushing on the diagonal is fine.

A charge requires the bull rushing character to move in straight line, which implies that the bull rushed opponent can only be pushed back in the direction of the charge. I would rule that on a charge the bull rushed character must be moved in line with the charge. However, there may be table variation on this.

[toastedamphibian]

You might just be thinking too rigidly. You can run 20ft down a 5ft wide bridge at alot of diffrent angles. They just mostly look the same when you map them to a 5ft grid.

Try this: draw a line from the center of the chargers starting square to any point in the square you want the target to end. Does it pass through the targets starting square? If so, your good.

Unless your restricting arrows to only 45 degree flight paths, the grid is just a handy abstraction.