I was in Lagos 2 weeks ago (I don't work for an airline, it was govt business) so I can give you info not gossip or hearsay.
From Lagos Airport to downtown I was put into a bullet proof vehicle and had a mobile armed police escort with 3 officers with machine guns tailing us all the way back.
I wasn't allowed out of the compound (in Ikoyi Island) unless I went with a driver and a policeman with machine gun. This meant walking round the supermarket with the policeman whilst buying a loaf of bread and some red bull
At night its even worse, no one ventures out of their compounds (no one = foreigners) without going in bullet proof vehicle and machine gun totting policeman.
I think you just end up staying in your hotel if you go there. I got out, its a big expat community, but it is dependent on having a sturdy vehicle, a driver and a guy pointing a machine gun.
At the airport, I was again escorted with the mobile police escort and I had someone with me until I got to the gate.
I actually didnt' have such a bad time, the bars for expats are good (e.g. Bottles on VI does very mean frozen margharitas) but it is restrictive. But I didn't have any problems when I was there and would go back (but not alone!)