The last phase, Portrait Gallery is all the way on the third floor of sea hag isle's tower. At least individually, 60 minutes is not enough to do all that's required to get up there. Even if you use a counterfeit, you'll still need the recipe key to get down to the third floor.
I believe this is a typo and an extra 0 was somehow omitted during the addition of the quest and it should have 600 minutes, not 60.
This quest  is called 'Life Sized Mirror', for Adventurers levels 241 to 241. Baron Nezak is the mistress in charge of this quest. Baron Nezak has heard rumors of newly-unearthed magic created by the archmage Vandemaar. Among the most powerful of the artifacts is a wand possessing tremendous power, harnessing the might of solar destruction. We have doubts that, at our current strength, Baron Nezak and our associated agents would be capable of capturing such a prize. Instead, agent, you must do the next best thing: judo together a counterweapon, a magnificent mirror that will nullify those tremendous powers. Do what you must, the information and raw material must be in our possession immediately. Upon successful completion of this quest you can receive: *Up to 123 quest points, 19 practice points, 0 archon points, 0 build points, 0 piety, and 20,000 gold pieces. *The item 'a small thank-you note indicating Baron Nezak's gratitude'. Item 'a small thank-you note indicating Baron Nezak's gratitude' is type treasure, alignment 0, made of paper (in (new) condition), has keywords 'small thank you note indicating baron nezaks gratitude bloodline passive'. This item weighs 0 stones and 5 pebbles, and is valued at 31,300 gold. This level 241 item has the attributes: nodrop nouncurse nodecay *Your Bloodlines must be equal to True to use this item. *Your current-roomflag must be equal to safe to use this item. *This item may be repaired 5 times. This is a heavy piece of fine parchment folded thrice. Written on the parchment in lamb's blood, in a gothic, brutalist font, is a genuine- sounding message of gratitude from Baron Nezak for completing some of their most difficult tasks. +++ a small thank-you note indicating Baron Nezak's gratitude will, when obtained, grant its recipient 1/3 of a passive Bloodline bonus. +++ a small thank-you note indicating Baron Nezak's gratitude will, upon granting the final 1/3 of its passive Bloodline bonus, imbue its recipient with 5 damage and one of the following affects for one Alyrian month's time: 'righteousness', 'pandemonium', 'desperation', 'pugilism', 'eye of the storm', 'perseverence', 'schadenfreude', 'shining path' or 'viper strike'. You have 60 Alyrian minutes remaining to complete this quest. Life Sized Mirror consists of: Phase 1: Journey to (NPK) The Hall of Mirrors. Phase 2: Journey to (NPK) A Mirrored Platinum Room. Phase 3: Journey to Glass-Walled Chamber. Phase 4: Defeat your reflection. Phase 5: Defeat a phantom glass beast. Phase 6: Journey to Portrait Gallery. *You are on 1 of 1 maximum simultaneous STANDARD quests.