What's the function of に here?

Question

So I have these two line in the book i'm reading, and i'm having a problem understanding the second one:

(And for the context, the main character is endlessly walking though a dark and silent ruin, where he can only hear his own footsteps)

ふいに、声が響いた。

その声に足を止めた瞬間、終わりを見失っていた永遠が唐突に幕を引かれる。

What confuses me the most here is その声に, what is the に particle modifying/interacting with here?

My best guess is that it is the indirect object for 引かれる... but there's a comma after 瞬間, is that saying that that に can't work in the next clause? that it should be working just for the first one?

So my attempt in translating this line is:

1 - "For that voice, in the moment his feet stopped, (something?) puts an end to the eternity that was losing sight of the end."

or

2 - The moment his feet stopped, that voice puts and end to the eternity that was losing sight of the end.

I am guessing this "eternity" is his endless walk through these ruins.

ps: I'm sorry that it sounds too literal, a lot of those words are new to me so I got their meanings mostly from Jisho.

Answer 1

This に just qualifies the next phrase, 足を止めた. The usage falls under the following definition in the dictionary:

７ 動作・作用の原因・理由・きっかけとなるものを示す。…のために。…によって。「あまりのうれしさに泣き出す」「退職金をもとでに商売を始める」

But speaking more specifically, it belongs to a certain use case where the thing before に is a stimulus that triggers the subject's (often spontaneous) reaction.

悲惨な光景に言葉を失う be struck speechless by a disastrous scene
人の優しさに涙する be moved to tears by the warmth of people
飛行機の轟音に耳をふさぐ stop one's ears against the roar of airplane

So, in this context:

その声に足を止めた瞬間
At the moment when the voice made him(?) stop walking, ...