A light twin flown correctly for pitch, yaw and roll will not fall out of the air in the few moments it takes you to confirm which engine has failed.
However, feathering the wrong propellor because you've decided that the immediate thing to do is pull one of the prop controls all the way back without verifying the problem, will most certainly seal your fate.
Students and line pilots have attempted to feather the wrong propellor in flight when their brain is full. I've seen it many times, and, like most multi-engine instructors, been the only thing that's stopped them from actually doing it. If an engine fails on take-off you need to feather without undue delay, but not without thinking or checking.
If you do not take the time to fly the aircraft first and confirm which engine has failed, you're a bloody idiot and one day you will get it horribly wrong.