Here's my first martial arts lesson to you not that I'm a master or anything:
Avoid fights at all costs. You don't want to be hurt nor want to hurt anyone. Running away is not cowardly, it is smart.
Thinking an instructor has nothing to teach you buy beating him up is just plain stupid, ignorant and arrogant. If you're a big guy, it can be relatively easy to beat up someone smaller that's untrained so a lot of times, these defense fighting methods are designed to give the smaller guy a chance to escape with as little injuries as possible in a conflict with a bigger guy.
It seems to me that you just want to learn more of a practical defense method of fighting versus a real martial 'art.' In that case I would look into mixed styles of fighting versus a strict style.