1) Short sentences are better - emphasizes the quickness of the action
2) Action comes before consequence: don't write "She fell back after I kicked her in the face," write "I swung a round kick to her face and she collapsed on her back." or something like that. And quit pickin' on the ladies!
But the passage I wrote was marked as "seems a bit much - can't be more plausible?"
Here's what I wrote:
"We jumped down the last flight of stairs just as the guard came out of the office. He pointed his bayonet at us and yelled at us to stop. I slid between his legs and while he hunched over to find me Ben jumped over his back and slammed into the wall behind us. I stood up and Ben kicked the guard in the butt, knocking him down."
So here's what I need to do (and I'm doing this as I'm writing it - so you're fully a part of the editing process!): Sentence by sentence, imagine the action and act it out if I have to, to see if it makes sense.
a) "...jumped down the last flight of stairs." So the two of them are on the ground level. "...just as the guard came out of the office." which I know is to the right of the stairs. So, the kids are at ground level and the guard just came out of the office. He's seen the bad guy down and out, so he's probably on his guard. The next sentence is probably pointless then.
b) "...pointed his bayonet..." well, if he's on his guard, his bayonet would already be raised, right? So maybe he just needs to yell "Stop".
c) "I slid between his legs and while he hunched over to find me Ben jumped over his back and slammed into the wall behind us"... ok, first I think this is kinda cluttered, now that I read it. It's just not smooth, and with action you NEED smooth. Secondly, Ben jumped over his back and slammed into the wall behind us? What's that? It's confusing. Plus this is all happening with a guy pointing his sharp bayonet at the kids in front of an office. So here's what I'm gonna have happen: the kids stop, because they're surprised, they drop to their knees in a fake plea for mercy, and get the guard to lower his bayonet. When he does, Ben leaps up and does a "hoo-ha" karate type of move, while Jeff scurries around the guard to the office. The guard twists to follow Jeff, Ben takes the opportunity to land a kick right between the guards legs. Drops him like a lead musket ball.
Now I just gotta write it!