We use it for most of our technology. It helps us achieve faster-than-light travel in our spaceships.

[Yep, he's basically saying that the stuff in his body is the same stuff used in ship engines]

They've tried getting me to retrofit before, but as you said, it's in a dangerous spot. I'm not risking letting anyone go back there. But no, I don't think I've ever heard of anyone's implant being forcibly removed. It's the only way we can use biotics in a practical way, so I can't see the Alliance ever trying to remove it from someone.