Minotaurs are monsters that have human bodies and bullheads. Minotaurs are well-known for their powerful physiques, particularly their heads, which can crush human bodies simply by pushing them.
They were commonly found on the 4th and 5th floors, and the minotaur they saw this time was probably not what Felicia had read about in the book. With its enormous body and half of it being a horse, what kind of creature could it ram with its head? At least not a human. And if it wasn't human, then he evolved according to his circumstances on that floor.
The room was not a good place for Allen to fight. He lacked the foothold to jump onto its head because the area was so vast. Moreover, the minotaur could not keep up with Allen's speed, so he had to move as soon as he stepped on something.