Slitherine

I have been playing through the tutorial campaign, but I cannot complete the suppression mission.
I am told to select the unmoved soldier and to select suppression (and static). I do this, then on the machines turn, he shoots one machine then gets killed.
After that, the remaining two troopers can't be selected and I can do nothing with them. They will not move or shoot?

Is there a bug or have I screwed up?