Final answer:
The attentional phenomena at play here is most likely inattentional blindness.
Step-by-step explanation:
In this scenario, the attentional phenomena at play is most likely inattentional blindness. Inattentional blindness refers to the failure to notice something that is completely visible because the person is actively attending to something else and does not pay attention to other things. It occurs when we are so focused on one task or stimulus that we fail to perceive other stimuli in our environment.