Lucy was running through the forest panting. He didn't know how far away from the clearing he had managed to lure the bear, but he was running out of mana and stamina. Just peeking into the Demonic Spark Bear's mind was troublesome, and since Lucy had to keep its attention away from Toz, he didn't just stop there as he started pulling and dragging on the darkness that was the Demonic Spark Bear's mind.
Lucy also had to hide from the bear while sprinting as fast as he could, further away from the pursuing bear. Eventually, he only had enough mana to either provoke the bear one last time or hide and escape, not both.
It didn't take much deliberation for Lucy to stop attacking the Demonic Spark Bear angrily chasing after him, demanding his life, which would have led to his death. Instead, he disappeared into the depths of the forest's shadows so he could circle back to the others and help Toz get out of the woods and to safety.