Other source:
Frieza is about to finish Piccolo off, but Gohan jumps in front of his energy blast to save him. He then fires a blast of his own at Frieza, but Frieza is able to deflect it. Frieza decides to transform into his final form to finish them off once and for all. Vegeta, however, comes up with a plan to stop him: he asks Krillin to severely injure him, so that when Dende heals him, he'll become much more powerful. Krillin reluctantly gives Vegeta a powerful blast, and the Saiyan falls to the ground. He stumbles over to Dende, demanding that he be healed. Though Dende resists, Gohan and Krillin convince him to do it.
