Complex sentence: Having heard nothing after the stipulated ten minutes, Eicke and Lippert returned to Röhm's cell to find him standing with his bare chest puffed out in a gesture of defiance, and Lippert shot him in the chest at point-blank range.
Split into simpler sentences: Having heard nothing in the allotted time, Eicke and Lippert returned to Röhm's cell to find him standing. Röhm had his bare chest puffed out in a gesture of defiance as Lippert shot him in the chest at point blank range.