Story related and CAN NOT be missed. Contains spoilers, first is quick form second is detailed and more...spoily?
- Go to Sanctuary
- Use Catch-A-Ride
- Get the Hyperion Adapter and install it
- Get vehicle and jump gap
- Find Corporal Reiss and his attackers (after going to Sanctuary)
- Get Power Core (Bonus for killing 20 Bloodshots)
- Contact Lt. Davis (Back at Sanctuary)
- Deliver/Remove/Install (in that order) Power Core
So go off the boat and move up the iced path to the catch-a-ride station, unfortunately Scooter is a dick and won't let you use one so you have to hack into it by getting a Hyperion adapter. So go and kill the enemies right by you, grab it, put it on the Catch-A-Ride station and go driving over the gap towards Sanctuary. Once you get there talk into the intercom and find out that someone is missing and you have to find him, once you do find him he tells you the core is missing and to avenge his death or something like that.
So go down and kill people basically, you get a bonus for killing 20 bloodshots...bandits, no idea. After you find the Power Core you can go back and talk to Lt. Davis again and he'll let you in. Go right when you go in and talk to him again, remove the old power core and put the new one in and bam, achievement unlocked, or you know, around this point.