Total Immersion Drills

I have had the Total Immersion (TI) DVD for some time now. I finally resolved to get off my butt and do the drills. To be honest it's tough to change into a swim suit and get into a cold pool when you're there solely to do drills.

I've done them twice this week (Monday and Wednesday) at Kennedy. They feel good, but I have this overwhelming fear that I could be doing something wrong. So, while I'm taking time and not swimming any distance worth noting and only doing drills I may be ingraining a non TI stroke while not receiving any cardiovascular benefit. I do trust the TI system, but what I don't trust is myself and whether I'm doing it right or not. I'm starting to wonder if a bad/mediocre stroke now that is well practiced is better than doing no swimming and just doing drills that may result in a good stroke, but quite possilby only a mediocre one?