in extremis
From Longman Dictionary of Contemporary Englishin extremisin ex‧tre‧mis /ˌɪn ɪkˈstriːmɪs/ adverb formal 1 DIFFICULTin a very difficult situation when you need to do something very extreme2 DIEat the moment of deathOrigin in extremis (1500-1600) Latin “in the extremes”