After escaping the construction site, you are invited to a LIMB upgrade as a secondary mission. DO NOT DO THIS. If you take this upgrade, later on on confronting Namir in the final boss fight, you will find defeating him impossible as your health has been so downgraded.
It is a nasty trick of the developers to include this lure: black marks!
In the end, I had to back trackx to a much earlier save as I could no longer enter just before accepting that ugrade: in fact I had to fight Mantis (Fedora again!!!)