Reminiscere miserationum tuarum, Domine,
et famulos tuos aeterna protectione sanctifica,
pro quibus Christus, Filius tuus,
per suum cruorem instituit paschale mysterium.
The rich and enlightening Lewis & Short Dictionary shows that cruor has a precise meaning: "Blood (which flows from a wound), a stream of blood (more restricted in meaning than sanguis, which designates both that circulating in bodies and that shed by wounding).
Remember Your mercies, O Lord,
and with your eternal protection sanctify Your servants,
for whom Christ, Your Son,
established the paschal mystery by means of His Blood.
The subtle meaning of cruor suggests to me an image of the blood and water flowing from Christ’s side.