Last night I was playing the first of the Protoss missions (Whispers of Doom). I had no problems getting through it, Zeratul still had full health, as did all of my stalkers (maybe one was at 75/80). I had also destroyed all of the hatcheries and thought, "Great! I'll be able to get all of the research and all of the achievements my first time through."
Then came the mad dash to the Void ship. I managed to blink over the first two rocks without leaving any stalkers behind, but the distance between the second and third rock was too short for the blink cool down to be over and I had to punch my way through it. Still not a problem yet. I quickly killed the spine crawler on the other side (I think maybe this was my mistake) then continued my mad dash. As I neared the ship my stalkers got shredded and I was left with only 2 stalkers, meaning that I missed one of the achievements (survive with 3 stalkers).
Are there any tricks to this part of the mission beyond what I did or was it just a mistake to stop and kill that one spine crawler. I'm still not sure what crazy thought ran through my head to make me do that. :)