Over-preparation is never a bad idea. As pianist Dick Hyman once told me, "If you want to play at 100%, you have to practice to 150%."
Maybe you already realize this—but practicing at steady tempi is essential. My dad always told his students, "You can play anything if you play it slowly enough." Playing with a steady beat—no matter how slowly you need to, to avoid mistakes—embeds the rhythm in your mind as well as the notes, and it's the pulse of rhythm that ultimately gives music its meaning and emotion. (When we were discussing practicing, a piano teacher once told me, "Imagine you're playing in a boat, and the music is the ocean, supporting you and moving you along. You don't have to control the ocean; just let it carry you.")
If you play something faster than you can, and you make mistakes, your unconscious mind remembers them and thinks that's how you want to play the piece—so before you can progress, you must go back and un-learn the mistakes, which takes twice as long. ;?) So ironically, the "fastest" way to learn anything is to play it slowly, then gradually build up speed, but never so much that you sacrifice accuracy.
You already have good ideas about conditioning yourself to avoid distraction (which I'm pretty sure is what you meant by "confusion"). Yes, you can try to play where there's ambient noise. Or you can invite a family member or friend to be in the room, doing other things, while you play.
But you're probably already better at this than you think. You can probably have a conversation with someone at a party, even though many other people are around talking and making noise, right? Music is just another kind of conversation (especially when you're an accompanist, "conversing" with the soloist; but you're always "conversing" with the audience, too).
It all returns to the same thing: being in the moment, staying in tempo, listening. Once you get a piece into your body at a steady tempo, accurately and with the feeling you want, you have a lot more than just the music at your disposal; you have an integrated experience.
It also helps me to remember that music is much bigger than just me. It's great being able to play music for myself and others. But I'm not "doing" it; I've just allowed myself to be a vehicle for it. That helps keep my ego at a proper level.
Finally, visualization is also huge. I once read an interview with a world-class athlete who was also a practicing lawyer. The interviewer asked her, "With a full-time law career, how do you possibly find time to practice your sport?" She replied, "I always schedule a few free minutes between clients. At those times, I sit back, close my eyes, and imagine myself playing exactly the way I want to."
So no matter how much time you spend actually playing your instrument, it's vital to spend time imagining yourself performing beautifully and effortlessly. Your unconscious can't tell the difference between fantasy and reality (which is also why people who imagine bad things often end up even less able to cope with reality). Imagining you're already successful convinces your mind you can do it, and that you can trust yourself.
Music comes from the unconscious mind. Our job is to learn it as well as we can, then get the heck out of the way and let our bodies do what we've taught them to do. When we're under pressure, our egotistical conscious minds think they must "take charge" on every level to guarantee our survival. But I don't even know how many muscles are in my arms, hands and fingers—so how could I possibly consciously control them? It's silly. (Even someone who's actually studied anatomy, and knows where all that stuff is, couldn't possibly coordinate its movements on such a scale, with such accuracy.)
In the long run, we must all find our own ways to prepare ourselves to play as well as we want to. Everyone's different, with different goals and expectations, so there are many approaches to success, both physical and mental. But ultimately it's all about conditioning yourself to trust yourself and let yourself do what you can do. The more you practice and visualize that way, the better you get at it, no matter how much else is going on or how many people are listening.
If you'd like to read more about the importance of mindfulness and trust in music, I can recommend Kenny Werner's excellent book "Effortless Mastery".
Hope this helps! Good luck!