Now the next chapter guys, its the chapter nine : Apprehension. In this chapter you will find a massive blow from the destroyed train, and you will swam a bit, also there are some soldier again, bunch of barnacles and other aliens, and the new weapon, guess what? The Crossbow. Lets take a look for the Black Mesa Source Walkthrough – Apprehension.
Drive the train forward until you reach a platform on your left. Bail out of the train before you reach the soldiers. The train will derail and explode. Find the ladder leading down to water, and climb down. The ladder will break and you will fall. Swim through the blocked entrance after breaking the board.
Head down to the water where the train crashed. Drag the barrels floating in the water to raise the broken catwalk by placing them underneath. Cross the catwalk into the next room. Follow the stairs and head upwards. When you try to walk across the platform above the water, it will break. Fall into the water and Swim to the next room before you run out of oxygen. Find the broken path under the water again, and make your way to the flooded stairway. Turn the red valve at the top of the stairs. One valve will explode, but the valve above the stairs will extinguish the flames. Move forward until a scientist is killed by an alien.
Clear the gap in the walkway to the other side of the room. Take the ladder in the closet and find the scientist. Talk to him about the alien, and head to the top layer of the room. Drop down into the cage and grab the crossbow. The cage will drop into the water. You will need to fight the alien. Once the fish is dead, swim to the metal door under the water. Turn the red override valve. Swim through the metal door and continue to the stairs. Find the door marked with 2 and open it. Find door number 6 and move through to the drum storage area. Kill the alien or avoid them. Move down the stairs and prepare to kill some enemies. Move through the broken doorway and clear the gap. Turn left before the stairs and the catwalk will break. Jump across the missing pieces of the catwalk and find the sign for the generator room.
Jump in the water and swim to the next area. Walk towards the generator controls and go up the ladder. Press the button on the console and take notice of the pistons. Jump across each set of pistons without getting flattened by them. When you reach the next catwalk, continue on until you reach a room with enemies. There will be a scientist who will unlock a glass door and let you inside.
Talk to the scientist who will then open the door to the cold room. The coldness of the room will sap your suit, causing damage. Move through as quickly as possible to the vents. You will not take damage in the vents. Crouch through until you reach a set of stairs next to a blue pipe. Go downwards and follow the hallway. Use the elevator and find the security guard. He’ll have a message for you, so listen carefully. Kill the new type of enemies in the bunker. They will be agile, so it is easier to use explosions than accuracy. Follow the stairs to the second floor. There will be an office with surface access controls. Throw the switch and move towards the metal doors marked with a 1. Enter a room with health and H.E.V. You will be ambushed by soldiers in the dark. They will apprehend you and drag you down a hallway.
Thats it for this chapter 9 Apprehension, if you find it hard to follow my instruction, here is the video.