The most reasonable inference that we can make from this excerpt is that Soviet troops were fighting somewhere else at the moment of the German invasion. And, since the Greman invasion came by surprise, the did not have enough time to mobilize their army back to the frontier to combat the Germans.
The son had showed his father a match. Whenever he lit the match, it filled the entire room with light, yet it was still small enough to fit into his pocket.
Explanation: the definition of oblivious is: not aware of or not concerned about what is happening around one, which basically means completely unaware
