Kylo wasn't entirely sure what he was looking for in his father's expression. Part of him desired fear as he proved he could take what he wanted, when he wanted. It was a feeling he was used to. But another part of him wanted something far more basic. When he approached, you could almost hear a little Ben Solo shouting, 'Watch me! Look what I can do! I'm useful! Notice me!'

And then the lightsaber powered down.

"It never mattered to you before, I don't know why I thought it would now..."

He wanted to force push Han right back out of that cargo hold. He nearly did. But instead, he just released his hold. The blaster bolt scorched the wall. Han was free to move his arm.