Only 19 out of 20?[edit | edit source]
The ground portion of this mission has either a minor bug, or simply an interesting narrative development, depending on your point of view. You will almost certainly find that you are initially able to administer telepathy suppressors to only 19 of the required 20 crewmen. The last man is hiding amongst the crates in the last storage room. In order to coax him out, you have to return to the beam-down point and then retrace your steps back to the storage area. When you do, he will have emerged from hiding.
The alternate view of this, of course, is that there's just a weird glitch in the mission.
Whichever position you hold, don't panic when you can't find that last crewman, and by all means don't beam out and then restart the ground portion of the quest. Although restarting will make the twentieth man appear, it's completely unnecessary. Just take a moment to go back to the beam-down point and return to the storage area.