Why did they say to Malik, "Let your Lord قض علينا" and not "Our Lord"?

The verse referred to in the question mentions the words of the dwellers of Hell in the context of the Qur'an's description of their torment in Hell, where they say: "And they will call, 'O Malik, let your Lord put an end to us!' He will say, 'Indeed, you will remain.' We have certainly brought you the truth, but most of you wereGhaters of the truth" (Az-Zukhruf: 74-78). The exegetes explain their attribution of 'Lord' to Malik as an urging and plea, not a denial of Allah's Lordship, as evidenced by their statement in another situation: "Our Lord, remove us from it; if we return [to evil], we will indeed be wrongdoers." They are then answered: "Remain humiliated therein and do not speak to Me."