Removing a protected kernel extension

I got rid of malwarebytes manually, rather than their uninstaller. There is one file left, a kernel extension. It is protected and I can't get rid of it. Even in safe mode the OS says macOS needs it. Etrecheck shows it isn't loading. The file is located in Library/StagedExtensions/Library/Extensions. Apparently the folder is protected. Is there some way to change to file or folder permissions to get rid of it?