Complex sentence: Realizing that a key pillbox in the center of the strong point would have to be knocked out if the company were to advance, Private First Class Brostrom, without orders and completely ignoring his own safety, ran forward to attack the pillbox with grenades.
Split into simpler sentences: Realizing that a key pillbox in the center of the strong point would have to be knocked out if the company were to advance, Pfc. Bostrom, without orders and completely ignoring his own safety, ran forward to attack the pillbox with grenades.