Point was to reinforce this guy's ruthlessness and recklessness, his continued defiance of authority.
So he answers:
"I'm not a boy anymore. Not so easy to kill. I do what I want and no one dares to interfere. I've outlasted them all. Even your commander, who has retired to the golf course."
Hmm. Got all the elements, the answer, the hidden threat, the bit of exposition (commander retired). But.. but it doesn't have much power. This is supposed to be a dangerous guy making a threat to the questioner (don't interfere), but it fizzles. Why?
Because it ends on the golf course.
If possible, paragraphs (especially speech paragraphs) should end on the note you want to leave in the reader's mind. So let's flip the sentences, so that golf course "no big deal" comes before the implied threat.
"I've outlasted them all. Even your commander, who has retired to the golf course. Anyway, I'm not a boy anymore. Not so easy to kill. I do what I want and no one dares to interfere."
Hmm. Now that I look at that, the most powerful and dangerous and threatening word in there is "kill". Can I revise to end on that? Let's see.
(Need one more revision pass so that there aren't so many short sentences... but maybe that's the way to convey that ruthlessness.)
I'm not sure that these little revisions matter all that much, one by one. But I think if we go into revision with the mindset of revising for power, for that jolt of extra precision, we will find many opportunities. And altogether, they will create more drama and meaning.