Interpretation of 「ミスターハスラー楽屋から火だすな」 in a song

Question

I'm trying to understand the lyrics of the song 刹那 by Creepy Nuts (link to Youtube video with lyrics).

I'm in the woods and the most enigmatic is this passage here. The lyrics go:

シラフじゃいられない まぁわかるが
ミスターハスラー楽屋から火だすな
キャリア、立場、時代かしがらみか？
ちょうど良い言い訳は見つかりました？

Starting with the meaning of ハスラー I found only this answer suggesting it is 薬取り扱う人, which I guess from the context must be drug user.

シラフじゃいられない まぁわかるが
ミスターハスラー楽屋から火だすな

My pure guess would be:

I can't stand being sober, but I guess I need to hide it (like a weed smoking-artist does not let the smoke out of the backstage)

Then for:

キャリア、立場、時代かしがらみか？
ちょうど良い言い訳は見つかりました？

I suppose:

Is it career, position, the times, or it's connections
That would be a good excuse (for not getting the job).

But my question is mostly about ミスターハスラー楽屋から火だすな (I'm not sure how it connects to the latter part).

Answer 1

I think this song saying about the mental state of a rapper challenging free style rap competition.

So based on this, シラフ seems saying rather "sane", "normal", "calm," etc. than being "sober".

ミスターハスラー楽屋から火だすな

ミスター probably means self proclamation to represent something.

ハスラー probably means a drug dealer as you said and a rapper from their own indie label founded by the profit.

楽屋から火だす, which literally means "put on fire in the backstage", it is an idiomatic expression; self-destructive, self-ruinous, shoot yourself in the foot, etc.

So, I guess it's saying "self-proclaimed renowned hip-hop hustler, don't shoot yourself in the foot."

キャリア、立場、時代かしがらみか？ちょうど良い言い訳は見つかりました？

I am not so sure the context of rap scene that much, but I guess this line says;

"Career, Status, Times, Constraints? Do you find any good excuse? (you can't perform well in the battle for not being able to win)"

But my question is mostly about ミスターハスラー楽屋から火だすな (I'm not sure how it connects to the latter part).

All in all, I guess the latter part is saying "stop bluffing or deceit and prove yourself".