The carts are not truly close enough that you can climb off them then climb back on then off again and make it to another cart in the space of one turn. But I suppose the narrator is somewhat unreliable because he didn’t specify how close they were to each other. Thus your actions do happen six seconds later than expected. Valet and Nori’s attacks fall on the rampaging horde of rats with all the power and fury of a teddy bear on a sleeping child. Whisper’s bolt does strike true but it’s a foregone conclusion.

The rats simply don’t resist their own demolition and focus on chewing out the supplies and foodstuffs on the cart with a single mindedness that defies description before the surviving few bolt for the edges of the woods. The lead cart is so chewed and raked that it appears structurally unsound.

As you gather in this wreckage, a single scream of fear, in the high purity of a child’s clarion echoes from the cart to the rear.

Which for once will be described as eighty feet behind the lead cart. Perhaps that is important. Perhaps the narrator is simply being unreliable again.