Big Oil, Day 1
Big Oil is a two day job, but the trickier part comes in day two. For day one, you're only tasked with stealing documents from a group of gangsters.
The documents are inside a safe somewhere inside the gang's house, so prepare for a firefight. Stealth is possible here, but it is not necessary, as this can be a quick in-and-out job. If you still choose stealth, be aware that there are mines in the yard outside the house - keep an eye out for the little exploders.
For a gun-toting approach, simply enter the house and gun down the gangsters inside. Find and bust the safe, snatch the documents, and book it back to the van. This can be done very quickly if everyone works to off the gangsters.
