Terminal Siege

You'll start in the second level of The Ferry station. There are miniguns on the caches nearby as well as additional ammo and explosives. Take a look around and grab the Heavy Mod from the office room at the back. There will be a minor zombie attack initially so kill them all and start preparing before talking to Marvin to start the ferry.

Put the fences, place mines and set up the MG's near the window. Upgrade your weapons if you haven't done so yet or if you have cash to spare, buy the appropriate ones for your level. There are also military caches around the area that you can loot so don't forget to check them out as well. Once ready, talk to Marvin to start The Ferry. Like before, you have to survive and defend the place. You have to keep moving and replace the barricades as necessary. These will help slow down the incoming undead and will you kill them safely with firearms.

Take note that there are also Boss Zombies among the waves and your machine gun's ammo is very limited. You can also use meat baits or exploding meat to take the heat off you. Finally in the last 25% of the horde strength, a screamer and several frenzed infected will arrive. The best way to deal with these dangerous freaks is kicking them to the ground and stomping them. Screamers can temporarily disable your party when it screams so deal with it quickly using explosives. Once cleared, ride The Ferry with the others.