Job Select isnt a new design, but is a keyworded version of a mechanic that has existed traditionally (both keyworded, with Living Weapon, and unkeyworded)
Nothing prevents its owner from venturing into that dungeon again if another spell or ability instructs them to, though they would have to start from the topmost room again

They look as follows (the dagger marks signifying the fact that it is impossible to tell the beginning and end of the sequences): Nidoran m, Diglett, Abra, Fire Energy, Starmie, Ponyta, Fighting Energy, Koffing, Pikachu, Doduo, Fire Energy, Gust of Wind, Machop, Lightning Energy, Gastly, Ponyta, Tangela, Grass Energy, Squirtle, Voltorb, Psychic Energy, Sandshrew, Weedle, Rattata, Water Energy, Drowzee, Poliwag, Fighting Energy, Charmander, Potion, Onix, Lightning Energy, Koffing, Magnemite, Psychic Energy, Pidgey, Abra, Metapod, Water Energy, Diglett, Staryu, Fighting Energy, Caterpie, Switch, Vulpix, Fire Energy, Voltorb, Machop, Grass Energy, Poliwag, Nidoran m, Rattata, Lightning Energy, Gastly, Doduo, Psychic Energy, Tangela, Sandshrew, Bill, Fighting Energy, Vulpix, Squirtle, Fire Energy, Pikachu, Bulbasaur, Drowzee, Grass Energy, Onix, Pidgey, Lightning Energy, Staryu, Charmander, Metapod, Psychic Energy, Energy Removal, Magnemite, Water Energy Poliwhirl, Maintenance, Farfetchd, Ivysaur, Pokmon Center, Machoke, Jynx, Full Heal, Kakuna, Double Colorless Energy, Porygon, Charmeleon, Maintenance, Poliwhirl, Raticate, Pokdex, Nidorino, Magikarp, Professor Oak, Magmar, Pokmon Flute, Porygon, Haunter, Energy Retrieval, Seel, Dratini, Double Colorless Energy, Growlithe, Wartortle, Full Heal, Dewgong, Defender, Kakuna, Magmar, Pokmon Center, Raticate, Seel, Revive, Nidorino, Kadabra, PlusPower, Dewgong, Super Potion, Arcanine The length of the sequences (77 and 44) which add up to 121 cards are too much of a coincidence to assume anything other than that they were printed on one single sheet and then separated before being inserted into packs

Although Innocent Blood is technically a more potent removal spell the ability to target Tragic Slip makes it actually useful and scale well into the late game where Blood typically becomes less effective