How could civilians leave the Far East?

Could Japan create the missing political shock by torpedoing a US-flagged liner evacuating civilians from the Far East?

Possibly, but such a US-flagged evacuation might not exist: civilians in Japanese territory would be interned, while others might leave aboard paid neutral British ships.

The viewer imagines a Japanese submarine sinking an American liner carrying evacuees and thereby supplying the missing political outrage. The first question is where such passengers could embark. Civilians in Japan or Japanese territory would more likely be interned than freely evacuated, while Americans elsewhere in the Far East still needed transport. Washington might therefore pay neutral Britain to send British-flagged ships to places such as the Philippines, turning civilian movement into another problem of neutrality and commercial bargaining.