(You can also discover how the G-Man seems to appear and disappear so suddenly. Around here you'll also be introduced to the mysteries of the floating blobs of energy which can teleport you all over the place. Watch out for steam valves which can hurt you (or, conversely, can hurt the monsters). When you come to an elevator shaft with a broken elevator, climb up the ladder and jump off into the upper level. In the main core you'll have to climb up ladders and time your movements so you don't get sliced in half by revolving electric beams. There's an underwater maintenance shaft that will lead into the main core.

Once both pumps are activated, find the auxilary reactor and dive down into the water. There's a path to the left and a path to the right - you'll have to work your way through a bunch of linear rooms brimming with monsters but it's nothing you can't handle by now. Here you need to find two pump rooms and turn on the pumps. Go up the elevator and find a large area with a big water pool underneath. Show him just how easily you ca bring yourself to use it on living creatures.

Once you go up the little lift you can go to the right where a holier-than-thou scientist introduces you to the egon. he needs to open a security door for you.

Half life lambda core