Krsna, being unlimitedly potent, decided to wait for an intelligent means by which He could simultaneously save the boys and kill the demon. Then He entered the mouth of Aghasura - SB 10.12.28

Expressions researched:
"Kṛṣṇa, being unlimitedly potent, decided to wait for an intelligent means by which He could simultaneously save the boys and kill the demon. Then He entered the mouth of Aghāsura"

Srimad-Bhagavatam

SB Canto 10.1 to 10.13

Now, what was to be done? How could both the killing of this demon and the saving of the devotees be performed simultaneously? Kṛṣṇa, being unlimitedly potent, decided to wait for an intelligent means by which He could simultaneously save the boys and kill the demon. Then He entered the mouth of Aghāsura.

SB 10.12.28, Translation and Purport

Now, what was to be done? How could both the killing of this demon and the saving of the devotees be performed simultaneously? Kṛṣṇa, being unlimitedly potent, decided to wait for an intelligent means by which He could simultaneously save the boys and kill the demon. Then He entered the mouth of Aghāsura.

Kṛṣṇa is known as ananta-vīrya-sarvajña because everything is known to Him. Because He knows everything perfectly well, it was not difficult for Him to find a means by which He could save the boys and at the same time kill the demon. Thus He also decided to enter the demon's mouth.