Lecture 2 covers MĀ 3 and MĀ 4:

MĀ 3 Discourse on the Simile of the [Border] Town (城喻經)

Pāli Parallel: Discourse on the Simile of the Citadel (AN 7.63), Nagaropama-sutta, PTS ed. AN IV 106

please consult Bhikkhu Bodhi (Numerical Discourses) pp. 1075-1080 (given as discourse no. 67)

MĀ 4 Discourse on the Water Simile (水喻經)

Pāli Parallel: Discourse on the Water Simile (AN 7.15), Udakūpama-sutta, PTS ed. AN IV 11

please consult Bhikkhu Bodhi (Numerical Discourses) pp. 1004-1006