My character, an old woman, has been knocked down, injured and can't get up. There is a crowd of people, spread across a park, who all witnessed the accident. From her view, at ground level, she is aware of a movement across the park, people turning towards her - but how to describe what she hears? - various exclaimations blurred into one. I'm trying, in one sentence, to put the reader down on the ground with her, before help arrives. I appreciate all suggestions.
First, think about all the different ways people might exclaim in such a situation. There will be some screaming in terror, others will laugh with unbelief because they didn't completely see what happened and mistake it for something staged or funny, there will be some calling for others to get an ambulance, some will silently run to the accident to help, yet others will shout orders what to do, and so on.
Next, think about the different ways you might summarize that. You can list it, as I did. You can describe the general effect of many different exclamations at the same time. You can try and describe the general mood of the exclamations (shock) or the behavior that accompanies it (tumult) .
From the function this scene has in your narrative, try and understand which kind of description most serves that function. Is there a character inside that situation? What effect does the situation have on them? etc.
Finally, simply try and write what you think works best and evaluate it on the next day. Revise as you see fit.
Your viewpoint character will perceive very little of all the crowd's reactions. Think of what the character will see and hear and describe it. The gabble of indecipherable talk, the exclamations of grief or shock or glee or what have you.
From the point of view, just declaring that the crowd exclaimed over it would convey much of it.
This isn't all in one sentence, and is probably not the answer you're looking for, but when I write exclamations from strangers in a large group, it looks something like this:
"Oh my gosh!" "What just happened?" "What is that?"
Of course, these are very vague exclamations because I don't know exactly what happens that is so surprising to everyone---and it's not in one sentence like you asked for, either. But if you're really stuck on using one sentence, I suppose you could say something like:
Exclamations of (horror and/or shock?) erupted around the park as _________.
Or something like that.