If you set blink distance to negative the "you will end up in block stop before that" detection still tests forward. That means that using spell provided below and looking up you can blink yourself into ground and if you look down it does not move you up.

{spellName:"Back",uuidMost:7119625452820907835L,validSpell:1b,spellList:[0:{spellPosX:3,spellData:{spellKey:"selectorCaster",params:{}},spellPosY:4},1:{spellPosX:4,spellData:{spellKey:"trickBlink",params:{psi.spellparam.distance:4,psi.spellparam.target:3}},spellPosY:4},2:{spellPosX:5,spellData:{spellKey:"constantNumber",params:{},constantValue:"-4"},spellPosY:4}],uuidLeast:-7378515317867525166L}