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I discovered this by accident when i phased out after collecting the 10 Smuggled Mana Cells and phasing in the middle of 3 mobs.
Sometimes it just takes way too long for the Bash'ir Phasing Device to drop. So what you do is after you collected the 10 required Smuggled Mana Cells, you phase out and fight mobs until *another* Phasing Device drops.
This will stay in your bags, even after handing in your quests and logging off for a couple of days, ready to use on the next daily reset, unlike the keys for Sunwell Isle which stays in your bags for a few hours (even if you take them out of your keybag) and then disappears.