死活問題 a matter of life and death●case of life and death●issue of critical importance●issue of vital importance●life-or-death [life-and-death] matter●life-or-death [life-and-death] problem●make-or-break issue●question of life or death●question of vital importance●vital question

死活問題〔~にとって〕 a matter of life or death (for [to])

死活問題となる〔~にとって〕 become a matter of life or [and] death (for)

死活問題に関わる mean the difference between life and death