The correct way of using toki

Question

My instructor told us that toki is used for placing an action that has happened at a certain time. For example:

さびしい時、友達に電話します。

But then how come this sentence is wrong? I'm sure that I used the correct particle, because I used this toki as a time reference to the main event which is Sara getting shot.

サラとサラのお父さんへいっしょにテクサスを逃げる時、サラのお父さの前にサラはうたれるので、人達がサラとサラのお父さんはゾンピみたいです。

I thought I used the appropriate grammar points but my instructor marked this whole sentence wrong. I don't know what I wrote incorrectly? I wanted to say that when Sara and her dad were escaping Texas, Sara was shot in front of her father because the people thought they were zombies. We learned that we use toki for placing actions that has happened but as I said my instructor marked it all wrong.

Answer 1

As the other poster has said, you're using とき correctly.

"When Sara and her dad were escaping Texas,"
→ 「サラと(サラの)お父さんが(いっしょに)テキサスから逃げるとき、/ テキサスを[脱出]{だっしゅつ}するとき、」

"because the people thought they were zombies"
→「 [人々]{ひとびと}は[二人]{ふたり}をゾンビだと[思]{おも}ったので、」
(lit. Because the people thought the two were zombies)

or more naturally:
→ 「二人は(人々にor[民衆]{みんしゅう}に)ゾンビだと思われて、」
(lit. The two were thought to be zombies (by the people), and)

"Sara was shot in front of her father"
→ 「サラはお父さんの([目]{め}の)前で[撃]{う}たれました。/ 撃たれてしまいました。」

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So I think you could say:

サラと(サラの)お父さんが(いっしょに)テキサスから逃げるとき、人々は二人をゾンビだと思ったので、サラはお父さんの目の前で撃たれました。

or

サラと(サラの)お父さんが(いっしょに)テキサスから逃げるとき、二人は(人々に)ゾンビだと思われて、サラはお父さんの目の前で撃たれました。

I think you would sound more natural if you said:

テキサスから逃げるとき、サラと(サラの)お父さんは(人々に)ゾンビだと思われて、サラはお父さんの目の前で撃たれてしまいました。
(lit. When escaping from Texas, Sara and her dad were...)

Answer 2

サラとサラのお父さん'は'いっしょにテクサスを逃げる時、彼女らはゾン'ビ'のようだったのでサラのお父さんの前でサラは撃たれた。How to use toki is not wrong.