Kreitler rollers. Those are nice!

In the early 80s, I worked in a shop that sponsored a pretty good racing team. Sometimes the racers would train on rollers in the shop. I remember one guy who could pedal and do anything at the same time. I saw him take his jersey off while riding.

I'm sure you won't need a helmet. If you fall, you have no forward velocity, so you won't be moving fast when you hit the ground or doorframe. And the helmet will get hot and wet and dirty quickly.