If I have to reload in a real life situation I know I'm in deep and the last thing I'm going to think about is how fast can I release a magazine and insert another.
It is just something that is not going to be on my mind. You can drill and practice and do it over and over and over all day long but till the real world day comes along you have no clue what is going to happen.
I do not practice seconds. I practice doing things the proper way each and every time. I'd rather take it slow and smooth than fast and fumble.