David Boreanaz actually was in a fair amount of pain during the torture sequences, as he had been in a car accident just before the episode was filmed. The accident did not severely injure him, but he is known to have sued the driver who caused the accident for the problems his injuries caused during his work.
Despite editing 5 minutes, when this episode aired in the UK it angered the ITC due to the violence and adult themes. The network quickly moved it to a later time slot than its usual 6:00 p.m.
A scene in which Marcus kills a sunglasses vendor was deleted, though in his next scene, Marcus still appears wearing sunglasses. Nevertheless, the actor portraying the vendor was still credited.
Spike referring to Angel as "a big fluffy puppy with bad teeth" is similar to Buffy's comment in The Harsh Light of Day (1999), where she tells Parker that the bite Angel gave her was given to her by an "angry puppy". Interestingly, Vampire Willow also refers to Angel as "Puppy" in The Wish (1998).