What is the definition of "exigent circumstances" in the context of a search and seizure application?

Exigent circumstances are defined as "those circumstances that would cause a reasonable person to believe that entry ... was necessary to prevent physical harm to the officers or other persons, the destruction of relevant evidence, the escape of the suspect, or some other consequence improperly frustrating legitimate law enforcement efforts." United States v. McConney, 728 F.2d 1195, 1199 (9th Cir.) (en banc), cert. denied, 469 U.S. 824, 105 S.Ct. 101, 83 L.Ed.2d 46 (1984). In United States v. Licata, we stated that