Lev's mind remains fully occupied with the process of considering his own mind, that of Kolya, and the narrative in which they've found themselves. Lev and Kolya, as well as the reader, are likely realizing that they've finally stumbled upon the fabled Russian partisans that Lev and Kolya are supposedly organizing. Notice the explicit mention of the partisans' different footwear. This indicates the vast differences between various partisans, who are not an official unit like the army.