be off the danger list
To have recovered from a serious illness. Primarily heard in UK. Uncle Harry is officially off the danger list! The doctors are releasing him from the hospital tonight.
be on the danger list
To be so sick that one may die. Primarily heard in UK. Uncle Harry is still on the danger list, so we're going to visit him in the hospital tonight.
be on/off the ˈdanger list
(British English) be so ill that you may die; no longer be very ill: He’s been extremely sick, but thankfully he’s off the danger list now.