Heist Prep: Tunnel Boring Machine

Tunnel Boring Machine is an optional prep mission featured in Grand Theft Auto Online as part of the The Diamond Casino Heist update. It is a freeroam mission needed to progress The Diamond Casino Heist. This mission can only be played if the player sent a picture of the sewer tunnel to Lester during Setup: Casino Scoping. Completing this setup gives players the option to enter the vault through the sewer during the Aggressive Approach. There are two possible missions for this prep.

Construction Site
"So, if we're gonna do some tunneling to the vault, we need a drill. And not just any drill. Take whatever you imagined, multiply it by the size of a building, and you're somewhere close. The only one in-state is all packed up on a flatbed at a construction site. I'll ping you the GPS now. Get it to the sewers, and I'll take care of the rest."

- Lester's briefing.

Overview
Lester informs the player that they must steal a Flatbed with a Cutter on it from Davis Quartz to be able to drill a tunnel to the vault from the sewer. After arriving and stealing the Flatbed, the workers nearby become hostile and the player receives a two-star wanted level. After escaping the police, the player must drop off the truck at the sewer access point to complete the mission.

Lester Dialogue
"That's the one, pretty big, huh? O-okay, you've got from now until the sewers to drop every innuendo you can dream of. As long as you lose the cops by the time you get there, I don't care."

- After stealing the Flatbed.

Convoy
"Do you know how many drills there are in the world that are capable of tunneling through the titanium-reinforced foundations of the world's most secure underground vault? Two. And unless you fancy a trip to Siberia, we'll be liberating our from a convoy en route to a construction site right here in San Andreas. Thing is. it's big. You'll need to commandeer whatever vehicle they're using to move it around."

- Lester's briefing.

Overview
Lester informs the player that there is a convoy transporting a Cutter to a construction site and that they need to commandeer it by any means necessary. This convoy can be in location such as East Joshua Road in Blaine County. Similar to the Construction Site mission, the player must steal the Flatbed with the Cutter on it and transport it to the sewers, then the mission will be complete.

Lester Dialogue
"Pretty big, huh? Now get your incredibly witty penis jokes out of your system and get ready to attract a whole lot of police attention when you make your play."

- When approaching the truck.

"I need this thing on-site, without a police escort. Lose the cops, and get it over to the sewers."

- If the player obtains a wanted level.