What is meant by not having your ego interfere?
Haha, I'm posting this as a question but I'm going to be a bit pompous and tell you the answer.
When I was a beginner (and I still am) in Jiu-jitsu, I had already been in the Martial Arts for 30 years and though I tried many things, and tried to 'empty my cup', I only truly learned what it meant to lose your ego when I started BJJ.
People who are black belts in other styles often are all full of themselves, think they know stuff, but they get out on the mat with a 2nd year blue belt female and get tapped out repeatedly and 90% of these so-called blackbelts in other styles, can not handle it. They get angry, try to use strength, not technique, still get tapped and instead of gaining some humility, quit. They just can't stand to have someone that THEY think is weaker or of the softer female gender 'win'.
Well, I'm here to tell you that EVERY black belt in BJJ has been tapped thousands of times on the way to their ranking. And they learn to welcome it, because without being tapped you are not learning anything. You're just full of your ego and wanting to 'win'.
It's a very hard lesson, and only 'easy' if you learn BJJ as a kid when you are pretty mellow and free of ego and hubris. For an adult to let go of 10-20-30 years of fighting 'skill', (but really fake skill in many cases), and put on that white belt and be willing to lose and be tapped is very hard. In fact you have to couch it in different terms than 'winning' and 'losing'. Everybody wins when ego is not an impedance.
Now you need ego. You must have a strong sense of self. You just have to be able to exercise some internal control over when you let it get in the way (or not).
Just some thoughts on the matter since we've talked about ego and insults and carrying a firearm.