"Everyone looks pretty grown-up after summer break"
Shinpachi finds himself in stuck in a completely different world.  That is when the Shinsengumi sends a berserk Yamazaki to pick up the bewildered Shinpachi.
We weren't infected because we were slacking off.
No fuimos infectados porque estábamos holgazaneando.
A gente se safou porque 
ficou de preguiça.