Khal was happy to see that Rubie was well and alive. She exceeded all his expectations as he never would have belived she would attack a Cultivator 2 Stages above hers!
This simply showed just how tight his bond with her truly was and just how terrifying she could be just to avenge him.
And this is why he must avoid her rage to break onto the surface like that in the future.
If she lost her cool in real life as she did back in that Digital World against Seila, she will die way faster as other Cultivators won't be as 'weak' as Seila was.
Also, to make it fair, even though Seila was on the Fifth Stage both her power and physical strength were depleted and on the limit thus lasting that long wasn't a surprise, could be said it was the norm.
"Beautiful Beast, what is her name?" as Khal was enjoying the warm sensation of Rubie's feather against his cheek, a calm voice appeared behind him causing him to turn around.