на том конце трубки - конец, noun in case, masc., sing.: End. Трубка, noun, feminine, in case. Singular. "at that end of the tube."

вот - here. Um. Adverb?

половина сотрудников - half. Um. number? descriptive? And yeah, noun plural, but not genitive.

Very good!

The house should also be awesome for survival in. Maybe only problem would be water supply, but if boiling makes water drinkable, you're good.