Did I hear a call for criticism?
I don't believe I've seen you here before, so first of all - welcome to FF&W! I hope your stay here is a pleasant one.
Right. Let's get down to brass tacks: as you mentioned, this part of the story is short. Very much so, in fact - it's almost like reading a précis of events rather than a retelling of them. There isn't much description; you'd expect something like an explosion to take up more than one eight-word sentence. You mention the smoke hurting your protagonist's eyes, which is good - more like that would really bring the scene to life. What about the heat? The scattered rubble and detritus? The smell of cordite/ozone/whatever you think a Voltorb explosion ought to smell of? You don't have to spend long o them, but little details like that are the meat on the bones of the story; it completes the image in the reader's head.
Having said that, it's not a bad starting premise, and certainly different: Trainer almost gets Pokémon, but is interrupted in the first line of the first paragraph by an explosion. It's the sort of thing that gets your attention
because yay explosions and it's definitely a compelling lead. If it had a little more description to back it up, it'd really be an opening to be proud of.
A few little mistakes I noticed:
I looked at the whole in the wall.
I think you mean a
hole, not a
whole.
A mouse with fire on it’s back popped out of the ball.
It's is a contraction of
it is. If you can't replace the
it's in your sentence with
it is, then use
its instead.
When punctuating direct speech, you end with a comma and begin the
they said part with a lower-case letter. You wrote this, for instance:
“Oh that wasn’t me.” He said smiling.
Which ought to be punctuated like this:
“Oh that wasn’t me,” he said smiling.
Other than that, I think the main thing you'd want to work on is, as I said, fleshing out your description a bit. It's all right not to know too much about the main character at this stage, since you started right in the middle of the action, but it would really help the story if you could flesh out things like the explosion, the mysterious boy, and the professor lying there on the ground - the things that you really want the reader to notice.
I hope that's helped a bit! I look forward to seeing more from you in future.