Complex sentence: During his second test-using Blakbeetle's medal-he easily destroyed a large number of Unitrix, but he got out of control and managed to only damage one Unitrix, who stopped him releasing the medal.
Split into simpler sentences: During his second test-using the Blakbeetle medal-he easily destroyed a large number of Unitrix. But he got out of control and managed to only damage one Unitrix, who stopped him releasing the medal.