does clock mean anything

what DOEs THE CLOCK DO what is the timer in the left corner PLEAsE sOMEONE Tell ME!!!!!!!!!

I fell like the clock is almost the same in every picture/video...

The round is over when you have killed all the zombies in that round, which can take you more or less time. So it's probably not to tell you when the rounds is over.

surly not when the rounds over because in this photo the round is over/ beginning and the red hand is at 15 to ...

does the clock tell when the dogs come or when the rounds over

whats with the clock what does it do???

Is this where you spawn in the beginning? Does clock run backwards on dogs?