unflappable

面对观众的激烈提问，主持人依然镇定自若

The host stayed ___unflappable despite the audience's aggressive questions.

手术中突然断电，这位外科医生镇定自若，平静地切换到了备用照明。

The surgeon remained ___unflappable when the power failed mid-operation, calmly switching to backup lighting.

绳索卡在崖边，这位攀岩者依然镇定自若，有条不紊地解开缠绕。

The rock climber was ___unflappable even when his rope snagged on a cliff edge, methodically working it free.