Tem Ray held the position of chief engineer for the RX-78-02 Gundam development project at Side 7's Colony 1, possessing high-level security clearance for the Earth Federation's top-secret mobile suit program. His singular focus remained the completion and perfection of the Gundam prototype. This intense dedication consumed him, resulting in significant neglect of his son, Amuro Ray, who lived with him on Side 7; Tem Ray was frequently absent and immersed in work, leaving Amuro largely unsupervised. Evacuated aboard the assault carrier White Base after the Zeon attack destroyed Colony 1, Tem Ray traveled with Amuro and other survivors toward Earth Federation headquarters in Jaburo. During this journey, his mental state deteriorated markedly. He exhibited severe stress, paranoia, and obsession, repeatedly voicing irrational concerns about the Gundam's safety and performance. This decline stemmed from immense pressure, guilt over the destruction of Side 7 and the deaths of colleagues, and the overwhelming burden of his project. His behavior grew increasingly erratic and disconnected from reality, culminating in a mental breakdown. Upon reaching Jaburo, he was hospitalized. Later encounters showed Tem Ray confined to a mental institution, largely catatonic. He displayed minimal awareness of his surroundings and no recognition of his son during visits, with no sign of improvement in subsequent appearances. Following his assignment to the White Base evacuation, Tem Ray received an official commission as a warrant officer in the Earth Federation Forces. His known military career ended with his hospitalization, and no significant recovery or further active role occurred after institutionalization.