Let $S$ be the set of all values of $\lambda$ for which the shortest distance between the lines $\dfrac{x-\lambda}{0}=\dfrac{y-3}{4}=\dfrac{z+6}{1}$ and $\dfrac{x+\lambda}{3}=\dfrac{y}{-4}=\dfrac{z-6}{0}$ is $13$. Then $8\Big|\displaystyle\sum_{\lambda\in S}\lambda\Big|$ is equal to: