
After each character has said their opening line, what do you want the audience to be thinking?

They'll probably presume that the cause of the accident is character 3. A twist could be that one of the other characters caused the accident. It's for you to decide who this might be, and create a character that suits your version of events.
In the opening lines there's a hint that something unusual has happened. It's for you to choose who this has happened to, and why.
If the drama is to work well, the audience has to feel some empathy [empathy: An awareness and understanding of another person's feelings, situation or motives. ] for the characters, so they care what happens to them.
To make this happen, you need to focus the drama on the characters. Hot-seating [hot-seating: To question an individual while they remain in character ] the characters could reveal important information about them, and provide ideas for scenes that help an audience get to know them.
When developing scenes for your drama, decide whether you want the characters to have met before the drama starts. For example, could the Ghanaian doctor have treated character 3 for injuries he got when he was fighting drunk?

Could character 3 have met character 1 when his gang caused trouble at the club at an earlier time?

This is a way of showing that the two characters had met before, little knowing that their paths would cross again. At the same time you can show something of what they're like.