I’m not clear on whether your response eliminated Thailand, Burma, and Vietnam as possible locations, so partially for tactical purposes, I ask, is it in Vietnam?
Wikipedia says that Southeast Asia includes "Eastern India . . . , Vietnam, Laos, Cambodia, Thailand, Myanmar, and West Malaysia, and also includes “Andaman and Nicobar Islands of India, Indonesia, East Malaysia, Singapore, Philippines, East Timor, Brunei, Christmas Island, and the Cocos (Keeling) Islands.”
Wikipedia also says that many anthropologists even consider Taiwan to be part of Southeast Asia, but I assume we don’t see Taiwan as part of Southeast Asia, and anyway, I’m pretty sure Taiwan stuff doesn’t belong here.