As the possibility of Japanese troops learning about the Dutch guerrilla base become more likely, Van Straalen received a radio message on 26 February from Marinus Vooren, commander of all Dutch troops in Celebes. Vooren ordered him to joined with the rest of the Dutch troops that were still holding out in Southwest Celebes; 14 days earlier, Van Straalen had already sent the non-combatants under Health Officer Waisfisz to join Dutch forces under Vooren. On 1 March, Van Straalen and his whole group started making their way through the Mekongga Mountains, reaching the coastal village of Loho Loho after over seven days. They hired ten boats and went on a four day crossing across the Gulf of Boni. With about 100 people, Van Straalen arrived in Palopo on 17 March, only to learn that Vooren had already surrendered ten days ago. His group made their way to Enrekang and report to Lt. Col. A.L. Gortmans, who was still holding out and refused to surrender.