I play it on ps3. I know that mission, i lost only one person on that mission actually.
Once I noticed how they were spawning I sent the one rookie I brought on the mission to push the button while the rest lined up to drop anything that spawned.
He made it to the button but 2 chrysallids survived for one round and that was enough to om nom him. After that I ran full out on turns where no chrysallids were in sight and gunned them down as they caught up to us. I managed to escape the area on the last turn before the airstrike
Oh also i had 2 heavy's, 2 snipers, 1 support, and 1 assault(the one who died).
First they came for the Socialists, and I did not speak out-- Because I was not a Socialist.
Then they came for the Trade Unionists, and I did not speak out-- Because I was not a Trade Unionist.
Then they came for the Jews, and I did not speak out-- Because I was not a Jew.
Then they came for me-- and there was no one left to speak for me.