Caribbean Pirate Achievement
On day 2 of the Rat job, bring additional meth bags to the trade, but steal your payment instead.
There are couple of different methods you can use to get this achievement.; the one you want to use is going to depend a lot on whether you are doing this alone or with teammates and what your gear looks like. The easiest method is with teammates and silencers, so it will be covered first. Regardless of method used, C4, safe cracking, or at the very least, speedy drill perks will make the job easier. Also regardless of method used, if they burn the intel before you get to them, you'll need to restart the day.
Method 1 - With teammates and silencers
If you have silencers, equip them (the M308 is my favorite weapon because it is a one shot kill even silenced). You'll probably want to split into 2-3 groups depending on how many of you there are. We will assume 2 groups for the purposes of this guide. Leave the meth in the van. That's what makes this method easier.
Group 1 will proceed into the building immediately in front of the van; we will call it Building 1. As long as you kill both of the guys at the bottom of the stairs before they can pull off a shot, no one else will be alerted yet (again, this only works if you're silenced). From there, head up the stairs, and take out all enemies you encounter. When you get to the room at the top, you're looking to see if there is any cash on the table. If yes, this is the room with the safe you need to crack. If no, proceed back down the stairs and through the door on the right to the next building (Building 2).
While Group 1 is doing the above, Group 2 will be proceeding up toward the truck that the gang members are waiting at toward Building 3; this building is on the right as you proceed up the stairs towards the truck. Hang a right between the chain link fence, and the building entering through the door that faces the center area you came from. From here, you'll be doing the same thing Group 1 is; clearing the building and checking for cash on a table. However, your building has 2 rooms and not just 1 when you reach the top, so be sure you check clear and check both. NOTE: If you have 4 players, send 2 of them into this building to better cover both rooms.
There is a ramp that connects Buildings 2 and 3 through the windows. You'll have to jump up on the window sill, and then crouch to get through. If the money and intel is in either building 2 or 3, you can toss the money from this ramp back towards the gang members truck and your escape. You can then pick it up on your way back to the van.
Depending on the level of assault you're under by the time you are ready to leave, it may be better to drop from the ramp to the scaffolding and down to the stairs, OR go back down through Building 3. If you go through Building 3, be sure to take the stairs all the way to the bottom, and go through the door on your right. There will be another door on your left half a flight up from the one you want. If you take it by mistake, you'll end up going the long way and having a lot more enemies to kill.
If you have been fast, silent, and lucky, you'll find the intel before they burn it. Grab it and your cash, then head on out. You will probably be in the middle of a police assault by the time you're ready to leave so be careful.
Method 2 - No teammates
Carry the meth up to the gang members truck and deliver it. Be careful not to run or toss the meth around a lot as they seem more likely to start shooting if you do. Once you've delivered all the meth, you will get a new objective marker letting you know where the intel and cash are. Head that way.
Once you get to the room, you have to open fire and kill them before they open the safe. Crack the safe yourself (C4, lock picking, or drill), steal a bag of cash and head back down. You'll now have to steal your meth back and escape safely.
Method 3 - Teammates but no silencers
This method is a lot like the second one except that you can split into groups. One group that goes upstairs to handle the safe and the intel; the other will handle the gang members around the meth and starts carrying it all back to the van.
While method 2 and 3 are easier to explain, they involve a lot more open conflict since you have to transport all the meth back to the van instead of just leaving it there in the first place.