In this line the reader gets the hint that there will be a larger event, which will occur after the "catastrophe" at the begging of the book, but that this calamity at the beginning will be the provider for what outcomes appear in the future. .
Also "With its door, or doors, wide open". May indicate that John Logan, who helped in the incident had another person in the car with him who also got out who may play a big role in the future of this novel. The reason this person is not mentioned when McEwan introduced the other characters is because Joe was not shore if there was another person with John Logan.
"We were running towards a catastrophe". This is clear that there is more of the event to be revealed, as what has happened so far cannot be that of a catastrophe. Also the way that Joe as the narrator describes it suggests that he isn't telling us the whole story, as he doesn't reveal the closure of the accident.
In these first few paragraphs we learn a lot about the two characters Joe (who plays the largest role and also as the narrator), and Clarrisa his wife, but especially Joe. "I don't recall dropping the corkscrew, or getting to my feet, or making a decision, or hearing the caution Clarrisa called after me." This shows Joe to be heroic and impulsive as he instantaneously starts running towards the center of danger without stopping to think. Also as the reader, we see parts of Joe as easily stirred or maybe even insecure, "this was the last time I saw anything clearly at all", as if any event could change his way of thinking and make his mind switch consecutively between secure and insecure.
From the beginning of the book, the reader can see that Joe pays huge attention to detail, "1987 Daumas Gassic", And the philosophic ways in which Joe describe the race towards the center of the field from a buzzards point of view. We can also see the huge attention to detail that Joe has when he describes the chivalrous run towards the middle of the field.