For Guan Gi, the surprise was way less than Saku and Alin, who witnessed everything that happened a second ago.
The battle was too one-sided, if it's called a battle that is, to be more precise, it was a complete annihilation. One second the lizards were charging at them and the next they were engulfed in purple flames and were burned into ashes. The process didn't even take a second, no sound came out of the suffering monsters, they couldn't even react before dying miserably.
"What in the...."
Saku was in total disbelief from the previous display, she even muttered those words unconsciously. The high-school girl Alin hid behind her friend Snow Peaks for fear of being struck by the purple flames which appeared too suddenly.
As for the last one, Guan Gi, his head moved between the place where the lizards perished and Lucy, who was standing in front of the other three.