Considering fatty pushed him into an on coming truck last chapter, MCs risking his life to save him /shrugs
Take it he says their strangers since noone remembers him from the last life ?
And unfortunately, the author decided to not give us any idea how the personality of the girl in the first life was :/ Bad writing on his part.
Also letting zombies loose in the school is a normal thing ? Can they really not find better ways to deal with dwindling resources ?