Count 40 time units of movement to be safely out of sheevar plasma blade striking range. The most dangerous foe, according to my loss statistics...
In skirmish mode they seem to have <=46, a plasma blade needs 8 to wield and use. Most of the time they just use a small fraction of their TUs, but once they come into killing range their seventh sense tells them to consume the reserved 20+ time units to kill your colonel.
Yeah really, I believe the sheevar infravision thingy is nonsense, it's taken as an explanation, but the algorithm must work differently. And they also know how valuable your units are, as they sometimes clearly ignore the cannonfodder they are supposed to consume their TUs on. So I believe the AI is cheating regarding these two aspects.