How is SIB for an engineer?

Since you're already pursuing a MBA, the knowledge needed for investment banking is most certainly being learnt. But I do believe practical application and how to discern what do where still requires experience and more so actual implementation of knowledge. 

A friend of mine did his Investment banking course at IIM Skills (online platform). What he told me was the thing that helped him the most to be clear on the subjects are the different projects and case studies they did during his time there.  And that pushed his confidence way up. 

So my suggestion, find an institute which provides guidance/mentorship and provides you a shot at hands on experience at it.

I would suggest IIM Skills simply based on how well recieved it was by my friend who had pursued it. Cheers!