Bear in mind that fiction often (usually?) takes liberties with the truth of a technical situation. That said, let's say your 4-engine aircraft is a Boeing 747-200 with JT9D-7Q engines (because that's what I still have a QRH for).
And let's say the paperwork says you weigh 620,000 lbs—it's an empty freighter you're ferrying from Santiago, Chile to Buenos Aires. You look in the performance tables and come up with the following:
- V1 is 130 knots
- VR is 140 knots
- V2 is 156 knots
- target rotation attitude is 16° nose up
Unbeknownst to you, the ground handling company decided to pick up a little money on the side and put 180,000 lbs of cargo on board for an equally corrupt operation in B.A.
So, you really weigh 800,000 lbs, the numbers for which are:
- V1 is 160 knots
- VR is 173 knots
- V2 is 183 knots
- target rotation attitude is 13° nose up
You stagger off the ground—God help you if you get a bad gust—with your reference speed 27 knots slower than it should be and your nose 3° higher than it should be. My guess is that you would be on the backside of the power curve, but whatever, your performance is going to be less than it should be.
Some miles ahead you have one of the highest MEAs in the world, 24,000 feet as I remember. Mt. Aconcagua at 22,841 feet (highest peak in the Andes) will be just off to your left. You often have difficulties getting that high that soon. You wouldn't make it today.
The solution: lower the nose and speed up.
And by the way, you're probably going to have to land short of B.A. for fuel. Personally, I'd go to Mendoza, Argentina.