All at once they fell over

... all at once they fell over like dominoes. Barney had pushed Ben who had fell over and bumped into Bob.This is how it had all started:

One drizzly day Bob was bored. Ben and Barney were at Ben's house. Bob sent an email to Ben saying let's go to the fish and chip shop. Ben sent an email back that said sure. So they all set off to the fish and chip shop. They all ordered chips. Bob ordered some ketchup with his. But ( very unfortunately ) when they were walking home home (in a line) Barney fell over therefore pushing Ben over therefore pushing Bob over.

And that is how the story went.