Complex sentence: They considered escaping to Portuguese Goa but when further transferred to Dehradun, to be detained there for years with 1,000 other enemy aliens, they found Tibet more promising, the final goal being the Japanese front in Burma or China.
Split into simpler sentences: They considered escaping to Portuguese Goa but when further transferred to Dehradun, where they were detained for years with 1,000 other enemy aliens. They found Tibet more promising, the final goal being the Japanese front in Burma or China.