Liu saw the first beam's trail...
It had passed very close to grazing the hyena's side, yes. But it had also passed dangerously close to where Liu was standing behind his beast in the designated tamer position.
If Ren had aimed more centrally toward the hyena's mass, the incredibly fast beam would have connected from the initial shot...
If Ren had targeted directly instead of forcing the hyena to dodge laterally...
The second beam would have passed through the hyena's body and potentially reached Liu standing behind as well.
It could have been lethal for Liu if the beam maintained coherence... He was standing too close to the impact zone. The beam would have dispersed somewhat after piercing through the hyena. But it would have been extremely dangerous regardless.
The second beam's trajectory...
