It's not a big problem to be in the wrong lane. You just change lanes like any other road. And like any other road, when you change lanes, it's your responsibility to make sure the lane you're merging into has space for you.
If you are in a wrong lane, the safest thing is to continue on it, exit the roundabout and comeback again or go around the roundabout.
Of course you could just not change lane, to the wrong way and safely correct your course later. This is preferable but people tend to get stressed out in those situations which is also bad for safety. Not to mention that a safe but ineffective road hasn't really achieved much.
I won't bother trying to expand on my comment to you, you're clearly not someone I'll be able to communicate comfortably with.