Start by putting out the fire in front of the hospital and eliminate the opponents
Go to the hospital. First, extinguish the fire by the garage entrance and eliminate the bodyguards. Then, open the safe and activate the lift. At the upper floor, after a short fight, take dynamite and put it in the barrel in the corridor on the right. Leave through the smashed wall and go down. Extinguish more flames, fix the structure and water the flower in the pot.
There is no way ahead. The working fan will keep pushing you down. Walk over the glass corridor onto the first building to climb across the window in the roof, into the locked room with color swapper. Change the color into red and you can disable the fans now.
Go up ahead. Make it through the door and use the teleporting device. You will teleport to the corridor, where you find a color swapper. Use it. Then, teleport back. Paint the climbing walls in the room to climb to the higher floor.
Make it over onto the hospital rooftop. Up there, you will face a group of opponents that you can throw down off the building. Then, disguised as a farmer, use the chicken to make it over onto the rooftop that Natalie is on.
Finally, you have to build a helipad for 20 000 bricks. Afterwards, fly the helicopter to your destination in the city center.