The soldiers started losing their composure when the flying demons wreaked havoc on top of the wall.
Without hesitation, Qiel sent forth more demons to climb the wall while they were distracted.
"Look! More demons are coming." The soldiers were too busy to deal with the annoying flying demons that didn't actually go inside the city. If the flying demons wanted it, they could fly past the city wall and enter the city through the opening. In the end, Layla's barrier covered everything except for the northern wall.
So, it wouldn't be weird if these demons tried to attack the city. However, it seemed that Qiel prioritized the wall.
After realizing that the amphibian, who had a Superior Demon inside the city was unable to cause any harm to the inside, Qiel knew that there were still people, possibly grandmasters, inside the city. Hence, it wouldn't be wise to separate their strength even further.