After Jeff discovered that his younger brother had left a window open and then used that to escape, Jeff started mildly panicking and ran back to the Chronivac to try to fix the situation. Jeff had turned his younger brother into a female feline and had no idea what trouble Danny could get into outside of the house, much less what the trouble for Jeff would be if Danny were missing when their parents returned home.
Jeff was surprised to find that whatever Chronivac package he had used on Danny to temporarily fully transform Danny into a girl cat had left up a timer on Danny's profile before more changes could be made to Danny. Jeff vaguely recalled some mention of optional timers to set the end time of the transformation, but didn't recall a profile lock timer. If Jeff had set it, he'd probably set the wrong timer in his hurry to tease his younger brother. This did not help Jeff's panic.
Jeff tried to think of a solution to find Danny. He recalled cats frequently marked their scent on things and hoped that maybe he could find Danny's scent. Jeff gave himself the nose and whiskers of a cat (recalling whiskers were also somehow involved in cat's sense of smell) and returned to Danny's room to see if he could smell where Danny the pussycat might have run off to.
Jeff only takes a few steps into Danny's room before he's nearly knocked over by how strong the scent his new sense of smell was picking up. Jeff wasn't yet fluent in cat smells, but that loud, strong smell was sending a rather obvious signal to Jeff. Jeff realized with a start that he had a growing erection. Jeff didn't need much other information to guess that his reaction to the smell probably meant that the smell was something like "fertile hot lady cat seeks tomcat to screw".
Now Jeff was even more worried about what might happen to Danny out there on the streets on her own. Jeff was also starting to feel very confused about chasing after Danny in this condition.