How do Gene’s and Finny’s walks back to the dormitory illustrate their respective characters?

Finny's walk back to the dormitory was nonchalant and easygoing. He was unfazed as usual, simply living and moving.

Phineas just walked serenely on, or rather flowed on, rolling forward in his white sneakers with such unthinking unity of movement that “walk” didn’t describe it.

Gene, however, broke into his West-Pointe stride.... offficial and formal. He followed the rules, whereas, Finny broke them.

“We’d better hurry or we’ll be late for dinner,” I said, breaking into what Finny called my “West Point stride.”