In developing a dramatic causality for progressing a screenplay, there are various relevant tools needed and I will be discussing five of them.
First of all is Timing: this refers to a cause that works when it lands at the right pressure point but note that If it's too soon there will be no stakes and this will get the audience bored. If the secret is revealed in act 1, act 2 has no tension, If you wait till act 3 after that already made the wrong choice, the effect hits 10x harder.
Secondly is the Talk value: Dialogue on its own does three jobs which is to reveal character, hide subtext and force a decision. Audience love to be surprised. They don't want to know or expect when a character death is pending. Every line of a dialogue must carry weight.
Thirdly is Symbolism, metaphor, and theme: you can create a deeper meaning for a character depth by attracting it to any symbolism, metaphor and theme that is intended to have same thought as those that you want to include in the overarching act and an example is worker dept.
Fourthly is the Arc of sacrifice: This includes having a character to sacrifice one step for the greater good and this is perfect for emotion. All these can relate to emotional character and the audience can relate through a connection. And Lastly is the Impact on other character: this showcase how death itself affect other characters they have connection to before their demise. Viewers learn more about character through their actions and reactions to conflict they face. For instance, If a surviving character is not affected by the dead character, it won't be memorable and an example is the harder they fall.