To take heart means to receive courage or comfort from some fact, and in this context the fact that some of them survived the encounter provides courage and comfort.
Context: They found the guardian virtually invincible, but I receive courage and comfort from the fact that some of them survived the encounter.
Hypothesis: They found the guardian virtually invincible, but I take heart that some of them survived the encounter.

Given this context, determine if the hypothesis is true (Yes, no, or unknown)?