Let \( \lambda \in \mathbb{R},\ \vec{a}=\lambda \hat{i}+2\hat{j}-3\hat{k},\ \vec{b}=\hat{i}-\lambda \hat{j}+2\hat{k} \). If \( \big((\vec{a}+\vec{b})\times(\vec{a}\times\vec{b})\big)\times(\vec{a}-\vec{b})=8\hat{i}-40\hat{j}-24\hat{k} \), then \( \left|\lambda\big(\vec{a}+\vec{b})\times(\vec{a}-\vec{b}\big)\right|^{2} \) is equal to :
