The Mosaic Law permitted consuming blood in some circumstances (life threatening):
If anyone, whether a native or a foreigner, eats an animal found dead or one torn by a wild animal, he must then wash his garments and bathe in water and be unclean until the evening; then he will be clean.
Jesus 'broke the law; to heal others:
He said to them: “If you have one sheep and that sheep falls into a pit on the Sabbath, is there a man among you who will not grab hold of it and lift it out?
Preservation of life comes before strict law keeping:
3 He said to them: “Have you not read what David did when he and the men with him were hungry? 4How he entered into the house of God and they ate the loaves of presentation, something that it was not lawful for him or those with him to eat, but for the priests only? 5 Or have you not read in the Law that on the Sabbaths the priests in the temple violate the Sabbath and continue guiltless? 6 But I tell you that something greater than the temple is here. 7 However, if you had understood what this means, ‘I want mercy and not sacrifice,’ you would not have condemned the guiltless ones.