It must be a day ending in "Y" because Eiryl being dumb again.
28 runs presumes youre buying all the Valkyrie items and doing Odin non stop. I dont do that because I'm on a
normal non-RMT infested server and I'm doing weapons on multiple chars. But anyways, presuming you're doing Odin only, 28 runs at an ungenerous ~7 minutes a run, including all the travel and zoning time, is 196 minutes. Thats about 6 Nyzul runs.
Thats not including the fact that an Einherjar run takes ~7 minutes, including all travel time, and can quickly be done between events:
Just finished Sortie? Go do a quick einherjar
Finished DynaD run? Go pop in for a quick einherjar
Finished Ambu? Go pop in for a quick Einherjar
Just got out of Odyssey? Go do a quick Einherjar
Cheating doing assault books and you're going faster than tags recharge? Einherjar while you let those timers reset.
Just finished an assault book? Go do Einherjar after trading it in to the rat.
None of this applies for Nyzul because its a 30 minute event, and shorting yourself into a quick run just hurts yourself because you're spending ~2k tokens to jump to 96.