If the shortest distance between the lines \[ \frac{x-\lambda}{2}=\frac{y-2}{1}=\frac{z-1}{1} \quad\text{and}\quad \frac{x-\sqrt{3}}{1}=\frac{y-1}{-2}=\frac{z-2}{1} \] is $1$, then the sum of all possible values of $\lambda$ is: