Movie reference: while suiting up for paintball Mike says "groovy," referencing the catchphrase of Ash Williams, protagonist of the Evil Dead series.
Peter Serafinowicz would play Pete in Shaun of the Dead; both his characters are antagonists to underdogs Simon Pegg and Nick Frost.
Movie reference: the last lines of the episode when Mike says to Simon, in Spanish, "there's a storm coming", it's a reference to the last scene in The Terminator.