Mr. Vivek walks $6$ meters North-east, then turns and walks $6$ meters South-east, both at $60$ degrees to east. He further moves $2$ meters South and $4$ meters West. What is the straight distance in meters between the point he started from and the point he finally reached?

- $2\sqrt{2}$
- $2$
- $\sqrt{2}$
- $\dfrac{1}{\sqrt{2}}$