This was not the only time the Irving Park store experienced an overwhelming stampede of customers. During the Second World War, the store was invaded by an "attacking force" of 15,000 shoppers after word got out that the store had acquired a supply of war-scarce merchandise. In a humorous look at the March 19, 1943 "invasion," the Chicago Tribune reported the following:

The attack started promptly at 9:30 a.m., Sears’ opening hour. Elbows and feet swung freely as the sale soldiers pushed their way through the aisles, riding roughshod over any opposition, to establish beachheads in all the aisles. Once through the doors, the forces split into a furious pincers movement.

The left flank, marshalling its strength, wiped out the alarm clock sector in 15 minutes; a couple hundred of those prize articles were sold by the brave clerks.

The right flank encircled the hosiery counter, seeking 51-gauge rayons. As the vanguard obtained one pair apiece, they climbed over the supporting troops in the rear, and retired to rest.

The spearhead stormed the escalators, bound for the sheets on the second floor. When the escalators stopped, they ran up. They went around the rope obstruction meant to keep them in orderly fashion. They brushed aside the store manager, W.W. Simmons, who was trying to maintain order. In half an hour the besieged sheet supplies were exhausted.

The $1,000,000 store, designed by Chicago architects Nimmons, Carr & Wright was the first of the company’s gigantic solid-walled stores in Chicago and featured the largest display window in the city at the time. Unlike previous Sears stores that relied on windows for light and air circulation, the Irving Park store incorporated the company’s newest store design concepts and was built without windows, utilizing artificial light and air conditioning.

The new windowless department store concept emerged in 1932 after Sears created a Store Planning and Display Department. This new department planned layouts for stores, diagrammed all display sections, and suggested space allocations for the various lines of merchandise. The department studied customer’s habits, flow of traffic into and through stores and sales records by stores and, on a national basis, by lines and departments. The department developed special lighting and display fixtures designed for optimum presentation of the merchandise.

The 1938 Store Planning and Display booklet, Profits Out of Space stated:

Only recently, say in the last ten years, has display graduated from the role of the shabby, often neglected little step-sister of advertising. Comparatively speaking, only recently has it come to the serious and scientific attention of forward looking store executives. And out of this recent recognition comes a whole new concept of retailing tactics. Facts, not fancy, now dominate display and it has become as exact a science as intensive research and statistical work can make it…

Especially in a Sears store is the importance of visual selling at its highest. We just can’t afford a salesperson for every potential customer that comes in. We’re out-numbered and in the interest of economical operation and low selling prices we must approach the "self-service" setup as closely as possible. Display becomes doubly important—good display becomes doubly profitable.

The Store Planning and Display Department insisted that serious attention focus upon factors over which the company could exercise control. First, a strict definition of the departments and of the number of price lines a store carried in relation to sales was developed. Second, a complete survey was completed showing what divisions were profitable and why, and what divisions were over- or underspaced. Third, a thorough examination of the merchandise presentation of each individual unit, plus a traffic picture showing the number of transactions, the average transaction, and other data pertinent to the nature and density of the business was undertaken. Finally, each store’s "profit history" was studied to determine what percentage of profits could justifiably be put back into the store for remodeling or enlarging.