Season 2: Till Death

Cat confronts Gabe about Sam ID-ing him and about Clara Bledsoe. He admits
that he was acting strange because he had been planning a Valentine’s trip to
Mexico for them.
The episode takes a hatchet to Gabe’s innocent excuses: we see
him getting a new passport photo while giving Cat some glib excuse about why he
can’t help her obtain a warrant for Sam’s apartment, and he explains this away
by saying he had planned on taking her to Mexico for Valentine’s Day, and
needed to renew his passport for the trip. At the very least, this explains
away the suspicious-looking transaction for plane tickets to Mexico that J.T
has discovered.