This man, who appears to be intoxicated, is shopping in a supermarket when he comes to a mirror. He appears to think that the mirror is simply a doorframe, because he then proceeds to try walking through it towards the "rest" of the store aisle. Upon doing so, however, he encounters the greatest challenge of walking through mirrors: his own reflection.
No matter where he tries to walk or how much he ushers this strange other man to go ahead and walk around him, he continues to constantly be blocked by the reflection. Naturally, he becomes frustrated and more impatient as the whole scene progresses.