52
The character of the President is introduced and his deep friendship with Leon established in quick cut flashbacks in the same scene that begins as he is already shambling towards Leon moments before he's killed. Just amazing writing 
How many first families is Leon personal acquaintances with? He's chummy with whomever Ashley's dad was who was POTUS in 2004 as well as the zombie president in office during 2013. I guess he works for the Secret Service so he gets invited to all their barbecues
Biden putting down his dog
Leon putting down Biden
Kristi Noem putting down her own dogs, Biden's dogs, and anything dog-like that happens to get too close
Zombified Adam Barton or whatever he's called does bear an uncanny resemblance to an (allegedly) non-zombified Joe Biden