Rocks'n'Diamonds

I'm stuck on Emerald Mind level 71. I either run out of spaceships, end up with an amoeba island that the spaceships can no longer get to, or run out of time if I tried to monitor when each spaceship hit the amoeba. Does anyone have a solution to this level?? I've tried starting the attach on the amoeba from a bunch of different angles with no luck, as I never can get the last two keys.

Here's is a screetshot of the level I'm referring to:

http://i99.photobucket.com/albums/l317/ ... pshot9.jpg

Thanks!

Wow I feel silly. As I was typing that I had a light bulb moment... do I even need all four keys to open the four doors??? Guess what? Nope.
I only need the red and the blue keys. Tricksy. Those are fairly easy to get. So now I just need to concentrate on getting the quota of emeralds (diamonds in this case). I figured I'd post in case somebody else gets stuck here.