Not doubting your knowledge, but fuel management if you just took off with two running engines within sight of the runway seems a stretch to me.
No not really. A fuel selector knob is turned and checked during pre takeoff check list. I can’t tell you how many pilots left it in the off position and took off. You have two selector knobs with three different sets of tanks. Each one has three positions. I’ve also seen pilots not see the fuel caps are not reattached after fueling and the air flow over the wings sucks the tanks empty in ten minutes.