Still plugging my way through this. Started and got through Sector 3, killed a security robot, and then had to move onto Sector 6. Picked up the Varia suit from the boss at the end, which means I can now go in ice and fire areas. One of which was Sector 5, which was next.
“Completed” Sector 5, and an alarm went off – I had to rush back to Sector 3 and run through it all to a room with another boss in. I now have the Wide Beam. The computer told me to go into the habitation deck, where I freed some animals. They’ll probably die now I’ve let them out.