How would the process work to withdraw a huge amount of money in cash from a bank?

You need.
2 pieces of verification and a photo I.D. If you want cash, they will give it to you in a bank bag and furnish that, but what they do not furnish.Is protection from leaving the place

Lol fortunately i don't have that problem but in the movies they take a case to carry it in ..

I never had that much money that wasn't a loan

American here. I live in NYC. this can be done same day. best to give the bank a few days notice. bring some 'help' so you don't run into trouble after you leave the bank. you'll need to provide 2 pieces of photo ID. there's a CTR to complete but the bank will do that for you. it happens more than you think