Fun fact, the chants in that movie are the same words, just different chant tones.

“Merciful Lord Jesus, grant them rest”

When the monks are smacking themselves in the face, it’s a very mournful tone (fitting, since these words come from the Requiem, or funeral mass).

Monks: “Pie Jesu Domine, dona eis requiem” *smack* “Pie Jesu Domine” *smack* “Dona eis requiem” *smack* (repeat

And when the Holy Hand Grenade of Antioch is being brought forth, it’s a call and response chant with a much more triumphant tone (which doesn’t fit the words, but is comical):

Call: “Pie Jesu Domine:”

Response: “Dona eis requiem!”

(Repeat)