Throughout the episode, Alice limps due to the sprain. But, when Sam presents the corsage to Alice and accompanies her down three steps and across the living room, she walks fine.
When Alice comes down to dinner, feeling better, the kids all have prepared a huge meal for the family. Mike and Alice act surprised. However, it is unrealistic that kids that young would be able to prepare such a large meal with literally no cooking supervision, as well as neither Mike nor Alice knowing about the dinner.
After Alice (Ann B. Davis) receives the flowers, Mike (Robert Reed) comes in and asks a question, to which she answers "No thanks, Mr. Brady. I think I'll be able to water them myself." That's when the boom mic's shadow is visible on Mike's face and on the wall behind Alice's bed.