The Thunderbeast had a clear field guide to help itself understand everything about it, whereas the giant red beast could only be judged based on one's own perception.
Unlike the Thunderbeast, which could be mass-produced simply by providing enough biomass, the giant red beast gave Bai E the impression of a special species that was difficult to manufacture in large numbers.
During his brief confrontation with the giant red beast, even while piloting a Mecha and fighting against it, Bai E hadn't discovered any way to kill or even defeat the opponent.
Before mastering the skills that could apply his own abilities that greatly amplified combat power to the Mecha, not even when manipulating what was known in the army as humanity's strongest war weapon, the armed Mecha, did Bai E have the slightest confidence in taking down an opponent one-on-one.