Things have certainly gotten tougher for you and your friends now. Once you gain control of your character, you will have 3 minutes to get to Liza and rescue her. Go along the only path you can until you are blocked by fire (hold the heal button if you happen to catch on fire), then shoot the pipes to continue. Keep going until you walk up a beam that gives way, prompting you to climb up to the next section.
There will be another pipe here to shoot, so wait until the first is out and continue. When you make it to a big room, walk along the center and then make a right and climb the vines. This will trigger another cutscene, where you rescue Liza and make your escape to the outside. When prompted, mash the button to move the truck, which will trigger the next section of the mission.
Press the fire button to pick up the grenade launcher next to you. It is now up to you to use the GL-94 to protect the truck. Keep shooting the vehicles chasing you as they approach, until Liza drives off-road and your truck ends up dying. Some enemies will come after you on foot from the front, so Jason hops in the front of the truck and grabs a pistol. Kill the enemies that approach (a convenient explosive barrel by the rock) until Liza starts the truck again, then she’ll drive until another cutscene starts, which ends the mission.
Rescue Liza from the burning building.