Joshua 8:22

‘ And the other came out of the city against them. So they were in the midst of Israel, some on this side, and some on that side, and they smote them so that they let none of them remain or escape.'

Now the men of Ai and Bethel were trapped, caught in between the two parties, and possibly the five eleph to the side. They had nowhere to go and were smitten down to the last man as God had commanded should be done to the Canaanites.