Why was the Invisible Man at Omniums?

From the text:

The place was already lit up and agreeably warm, and I decided to remain where I was, keeping a cautious eye on the two or three sets of shopmen and customers who were meandering through the place, until closing time came. Then I should be able, I thought, to rob the place for food and clothing, and disguised, prowl through it and examine its resources, perhaps sleep on some of the bedding. That seemed an acceptable plan. My idea was to procure clothing to make myself a muffled but acceptable figure, to get money, and then to recover my books and parcels where they awaited me, take a lodging somewhere and elaborate plans for the complete realisation of the advantages my invisibility gave me (as I still imagined) over my fellow-men.