Question

What is the meaning of mocdrill and what's its meaning

Answer 1

Mock drill makes it clear that it is just practice and there is no real fire. 

The phrase "mock drill" is a redundancy, because mock means an imitation, and drill in this sense means a practice, or "systematic training by multiple repetitions." So you wouldn't really have an "imitation" practice or rehearsal. The rehearsal is real, even if the emergency situation for which one were practicing was staged. So the drills are real, not "mock." 

Answer 2

A mock drill is a method of practising how a building would be evacuated in the event of a fire or other emergency. Usually, the building's existing fire alarm system is activated and the building is evacuated as if the emergency had occurred.