This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
戃 combines 忄 (heart/mind) with 黨, which likely provides the sound. The exact historical development is uncertain.
The left side 忄 suggests an emotion, and the right side 黨 is dense and complex. Picture a startled heart overwhelmed by a noisy crowd: the kanji evokes a feeling of surprise or alarm.
For トウ, imagine a sudden loud 'tow' sound startling someone: tow -> トウ, and the heart 忄 jumps in surprise.