Griffin have to run away from the big London store because the servants of the store had been arrived and Griffin was the culprit so, he has to be invisible, otherwise he will going to be arrested by the police for robbing the store.

Introduction:
Griffin, the protagonist of the novel "The Invisible Man" written by H.G. Wells, had to run away from the big London store due to a series of unfortunate events that unfolded during his time there. These events were a result of his invisibility and the subsequent difficulties he faced in controlling his newfound power.

1. Griffin's invisibility:
Griffin had successfully discovered the scientific formula to make himself invisible, but he had not yet perfected the process. As a result, he was constantly wrapped in bandages to hide his invisible state. However, during his time at the store, the bandages got dislodged, revealing his invisibility to the store employees and customers.

2. Panic and chaos:
Upon seeing an invisible man, the store employees and customers were understandably shocked and terrified. Panic and chaos ensued, as people screamed and ran for safety. The sudden appearance of an invisible figure caused a state of confusion, making it difficult for Griffin to navigate through the store without causing further alarm.

3. Destruction and theft:
As Griffin tried to escape the store amidst the chaos, he inadvertently bumped into objects and knocked them over. The invisible presence of Griffin caused further destruction within the store, adding to the panic and fear of those present. Moreover, in his attempt to flee, Griffin also stole some money from the cash register, further complicating the situation.

4. Pursuit and escape:
The store employees and security guards, realizing that Griffin was responsible for the chaos and theft, began to chase him. Griffin, using his knowledge of the store's layout and his ability to turn invisible at will, managed to evade his pursuers for a while. He used his invisibility to his advantage, slipping past security personnel and escaping their clutches.

Conclusion:
In conclusion, Griffin had to run away from the big London store due to the revelation of his invisibility, the resulting panic and chaos, the destruction caused during his escape, and the pursuit by the store employees and security guards. His invisibility, which initially seemed like a remarkable scientific achievement, became a burden that led him into a series of unfortunate events, ultimately forcing him to flee for his own safety.