Why was Benny on the wrong side of the river?

Because while in the water he decided to go onto the wrong embankment. Now he has to find another boat or a bridge to cross the river.

My view of it was that Beni is on the side where all the Egyptians were, whereas Rick was on the side where the Americans were...

"I'm trying to see things from your point of view but I cant stick my head that far up my ass."

I always thought it meant that O'Connell is on the Hamunaptra side. O'Connell would known that. Beni must cross somehow.

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The story is king.

Cause horses can't swim.

And yet Beni and the Americans still managed to get to the entrance of Hamunaptra at the same time as O'Connell...

When he swam to shore after leaving the boat, he chose the side of the river away from his destination. All the horses and other stuff that he had on his side would have to be transported to the other side of the river, which would be a pain.

Because Benny was always on the side of everything.