Once again, search the area where the last battle has been fought to replenish your supplies. When you're done, take the passage pictured above; O'Neal should already be waiting there.
Follow O'Neal, but don't hurry too much because you'll be regularly plagued by quite numerous packs of Xenomorphs. When you reach the colony's complex, head for the closed door located on the left (the above screenshot). Examine the area to find another Dog Tag (PFC C. Bradley). Move onwards, but stay on the main path, and you'll find the entrance to a new building.
Go inside and start exploring the narrow corridors; you won't come across any aliens for now. When you get to the closed door, use the welding torch the only way you know how to get through to a huge garage.
Take a moment to search the first part of the place - you'll find a Dog Tag under the stairs on the right (PFC M. Jelley), and a full set of armor on the upper platform. Afterwards, go to the end of the garage to stumble into Bella and Reid.
The conversation will be cut short when alien Lurkers show up. Apply the same tactics as in the last part of the previous mission: detect them with the flashlight and the motion tracker, then attack from a large distance using the best weapon you have. If you can, don't let them charge to perform a melee attack.