Depends where in Lagos you need to go to.
Ikeja? Certainly. I've done it myself dozens of times.
Ikoyi/Victoria Island? Forget it. You may get lucky, but you can be stuck for hours in traffic.
Most people doing day trips meet up at the Sheraton in Ikeja (assuming that you don't have a private office in the area). It's safe and they have decent-ish restaurants (or Goodies Pub if that's your preference) where you can meet in relative privacy.
Alternatively, consider basing out of Accra and doing a day trip across from Accra to Lagos. It's only a 45-minute flight and gives you a longer day in Lagos. I'm based in Accra myself so this is the strategy I usually use. In 40+ trips there, I've only ever stayed overnight maybe 3-4 times. You can do the same from Abuja if you want to stay domestic (the domestic terminal in Lagos has easier access to Ikeja anyway). It's often quicker to fly from Lagos to Abuja and then drive to the Hilton/Sheraton in downtown Abuja than it is to get from Lagos airport to downtown Lagos!
Safety is an issue in Lagos, but basic precautions (like being picked up by someone from your local contact and verifying their identity) will usually suffice unless you are a high profile potential target. In which case though, you'd be talking to your personal security advisor about this rather than posting on FT!
