Complex sentence: In his first session, he had run out of material; improvising, he suggested that students speak about "something that made them angry", and discovered that the technique made speakers unafraid to address a public audience.
Split into simpler sentences: In his first session, he had run out of material. Improvising, he suggested that students speak about "something that made them angry", and discovered that the technique made speakers unafraid to address a public audience.