Exit the same way and continue up the stairs. Smash through the wood and jump through: there are supplies in here. At the top of the stairs are two sealed doors, but a window next to them has been broken and is boarded up 10. If you run out of barrels, you can pull radiators off the wall and throw them. Using your gravity gun, lob barrels at them to knock them over so they can�t shoot you 9. There�s a hole in the floor itself (not the one in the middle of the room): drop through it and go into the next area. In the next section, you�ll be in another prison block. Three fast headcrabs fall through a skylight. Exit the room by climbing the steps and following the catwalk to a door. Make your way to the steps on the other side watch out for barnacles 7. (Note: The turrets start shooting randomly for a few seconds when knocked over so be careful not to get shot.) Through the next door is a flooded room. Two more turrets appear 4 these you can push over with the gravity gun 5 or pick them up and throw them 6. In the small rooms around there are supplies. Climb over the broken fence 3 and follow the path around to the left. Use your gravity gun to knock over the turret that is sitting there shooting antlions. To your left will be a prison cell with a hole in the back of it 1.
