Please just get therapy. Christ.

Probably not pure mercury but one of the extremely nasty mercury compounds that is easily absorbed through the skin. The victim was very sick.

Just needs to emit some bone-cracking noises as its joints go the wrong way to make a normal person vomit and faint

According to the article search and rescue was “unsuccessful” so we may assume all hands were lost. However bad, it was their last. I know these aren’t necessarily very fine people or anything, but I mourn what might have been if they didn’t go to the service of a futile and costly invasion.