[T6 ZM] Character Quote Glitch/Feature?

[GOLD3N 4RM]

I've been testing quotes out in Black Ops 2 Zombies (because I am making a sound overhaul mod) and I notice something

When a game plays a quote for a certain character, as soon as a previous one finishes they go quiet for a few seconds.
(This phenomenon occurs for everyone)

Here's a visual representation:

Character Glitch: Black Ops II

For a while I figured it was a bug, but now I wonder if it was one different. The soundbank includes a lot of quote files and when I came across either zm_buried or zm_alcatraz, I found a silent_loop file. So I started thinking if whether or not the "silent" file (or something else) is played in order to give a character a cooldown time.

Question: Does this silence have to do with the sound build? Or is this just a bug/glitch?

As far as I can tell, there has been no other games (Treyarch at least) where this has occurred.