This you need to check out the mechanism more...
LAH is a hydride attacking, that's why it goes through Sn2, those are usually not under basic condition, so the O can't leave, u get an alcohol
H2NNH2 is like amine attack, you should check out how amines react with carbonyls, that'll let you understand why mechanistically the products are the way they are. Orgo is hard to explain w/o drawing board, sry
