X-42 - The Giant Robot Scorpion
If you want, feel free to just fight it. You can use the sonic emitter or the LAER and you’ll be fine, for the most part. You better have a lot of stimpaks to heal up the damage though, and a lot of ammo. There are some other options though.
The giant scorpion has about 2,500 HP, good defenses and a strong laser attack. The blast takes a few seconds to charge, but it has a huge blast radius and emits radiation too. You really want to be inside one of the side buildings when it goes off, and stay away from the windows.
There are some creative options for this course though. You can start by running into the nearest bunker to the right. If you jump onto this computer, you can set up some target drones and have them enter the course. This will draw the X-42’s attention for a long time, which will let you continue to the other bunker on the right. Note that if you have 100 points in Science, don’t bother with the following steps. In the back left corner of the room, you can access the emergency shutdown terminal. If you can hack this Very Hard terminal, you can end the fight now. Use the drones for cover and run for the other set of stairs and then look for the computer.
If you don’t have the points in Science, you can then go to the other computer inside the bunker to the right. You should be able to just use the computer and activate the backup generators, which will cause a massive explosion and take about 1,000 HP off of its health.
If you want, you can also go to a computer in the front-left corner. The one closest to the door doesn't have anything, but the other has a terminal that will let you activate the turrets and turn them on the giant scorpion.
The last step, if you can’t hack a Very Hard computer, is to grab a mint condition LAER off of the table in the bunker in the back right. Note that you should be able to jump over the rails to save yourself some pain. This weapon will do a lot of damage to the X-42 giant scorpion, so if you don’t have something equally good, run inside and grab it and the ammo. Then just start firing and drain the rest of its health while using the buildings for cover.
Once it’s dead, make sure that you search the remains. There’s a final setting for the sonic emitter, “roboscorpion," inside it. When that’s done, get onto the raised catwalk and go through the door to reach Dr. Mobius’ lair.