A room in a hospital used for performing surgery (originally designed for operations in front of observers).

(idiomatic) Phrase used to indicate that if a specified activity is not continued or carried out, those who seek to disrupt normal activities through terror will have succeeded, which is an unacceptable result.

even so

Important, indispensable, crucial.

(set phrase) Time is an essential consideration (in regard to an action or response); haste is necessary.

(chiefly US) To make the decisions; to be in charge; to give orders.

(idiomatic) Crazy, mad or insane. / (idiomatic) Close to or in close proximity to another location.

(idiomatic, colloquial) Used to confirm preceding utterance, while implying that what was said or asked is an understatement

(idiomatic) Used to suggest an understatement.

(idiomatic) Notwithstanding.