in extremis
adverb /ˌɪn ɪkˈstriːmɪs/
  /ˌɪn ɪkˈstriːmɪs/
(from Latin, formal)- in a very difficult situation when very strong action is needed在危急关头;在紧急情况下;在绝境 
- at the moment of death临终;弥留之际 
词源Latin, from in ‘in’ + extremis, ablative plural of extremus ‘outermost’.