“Mauve alert was the universally recognised colour for danger, signifying the highest level of...Mauve alert
“Ultimate Code Red was a declaration by the United Nations, signifying a large-scale alien...Ultimate Code Red
“A quarantine beacon was, according to the Tenth Doctor, a signal that prevented someone from...Quarantine beacon
“Red alert was used by humans to signify the highest level of danger. When the Ninth Doctor and...Red alert
The following 19 pages are in this category, out of 19 total.