Guard penguin

Maybe they have got something.

 But go back 40 million years and it was a different story.
Back then scientists say a race of mega penguins that weighed in at 115kg and were as tall as people roamed the Earth.

I can confirm this.
I've seen them out the window of my DeLorean.
They also breathed fire and had toxin-laced talons.

Maybe it's not guard penguins ? I am assuming you are refining to the guards at the ice wall ? Instead..... Maybe there is a super race of humans who live on the other side of the ice wall who are keeping ordinary humans from seeing the ice wall ? When their special powers or advanced detection devices detect humans, they come over from behind the ice wall and zap them. This would account for those "mysterious disappearances".

Maybe it's not guard penguins ? I am assuming you are refining to the guards at the ice wall ? Instead..... Maybe there is a super race of humans who live on the other side of the ice wall who are keeping ordinary humans from seeing the ice wall ? When their special powers or advanced detection devices detect humans, they come over from behind the ice wall and zap them. This would account for those "mysterious disappearances".

I believe that they just teleport the "normal" humans to the opposite side of the ice wall.  This would account for those "mysterious trans antarctic expeditions".  It is the obvious conclusion from given evidence.