Gravis waited for 55 minutes, but nothing happened during that time. No one from the Darkness Sect came for him, while Lasar and Old Man Lightning were still away. They were probably still fighting, which was a surprise for Gravis. They should have actually finished by now.
Gravis guessed that they might have already finished fighting but didn't want to distract him. Wanting to know the result of a fight was also a motivation to return alive. Maybe they thought that Gravis would grow "content" when he knew that Lasar won. Maybe they thought Gravis would lose his calm if they told him that Lasar died.
Of course, all of this didn't matter to Gravis. He was used to his companions dying. Something like that wouldn't affect his mind by much. He still had a connection with his companions, but his will allowed him to quickly deal with grief.
