As you step through the door, you’ll find this cell directly in your path. Finish all three to open the ancient door.
It seems to be a part bug and part intentional. Help, The Gates To Mothers Cradle Are Locked! Once you have located them all, head back to the lab.
It can absorb a lot of damage and it looks pretty cool. Some will regard the Shield Weaver Armor as the best armor set that you can get in Horizon Zero Dawn. It is a rare inventory item that takes some work to obtain. The Shield Weaver armor is an advanced armor set that was created by the ancients.