Learn Finnish: Miten selviydymme tässä armottomassa paikassa? - How will we survive in this merciless place?

Armoton ends in the suffix -ton (meaning '-less' or 'without'). When inflecting these adjectives, the stem changes to -ttoma- (or -ttömä-). Because it modifies paikassa (in the place), it must match its inessive case ending -ssa, giving us armo + ttoma + ssa.

Why does the single "t" in armoton become a double "tt" in the stem -ttoma-?

This is an example of inverse consonant gradation. For words ending in -ton or -tön, the dictionary form (nominative) is actually in the weak grade. When you inflect the word and the stem opens up, it switches to the strong grade, doubling the t to tt.

Why do we use the inessive case (tässä paikassa) instead of the elative (tästä paikasta) with the verb selviytyä?

Selviytyä (to survive/cope) usually takes the elative case when you mean surviving from or making it out of a situation. However, using the inessive case here changes the nuance: it emphasizes staying alive or coping while inside the place, rather than escaping it.

What is the root noun that armoton is built from?