Further details of Gaal's life are given in "Forward the Foundation". After the exile, he carried the crises tapes recorded by Hari Seldon there. He also oversaw the construction and installation of the Time Vault. Gaal Dornick became one of the key workers with Stettin Palver on Seldon's Plan, reporting directly to Seldon on its progress as they refined it. After Seldon's death, he moved to Terminus. Seldon's own version of the Prime Radiant was bequeathed to him and shipped after Seldon's death. Wanda Seldon had Hugo's Prime Radiant. Since Bor Alurin is stated to be the only social scientist present in the First Foundation, and the Prime Radiant appears later in possession of the Second Foundation, it's likely that he didn't stay permanently in Terminus.