Originally Posted by
pureauthor
Well, the question wasn't directed at me, but I'll try my best to answer anyway (in some ways I believe I'm more suited to answer this rather than Kieran, since he has yet to play Fate/Extra):
Firstly, if not for 'his act of stupid' he wouldn't be able to do it 'the easy way' either, because Shirou would have gone instead, and Shiki would be back at Home Base demanding updates on Arcueid's location every fifteen minutes.
Secondly, the 'easy' way here is anything but. Barring the initial four days memory loss trial, he's now amongst 127 other Masters, any one of whom could be Arcueid's current Master, and the situation being what it is, almost all the Masters keep the information on their Servant very close to their chest. MEoDP is hardly a universal panacea for this situation, and Shiki knows it too, which is why he hasn't taken his glasses off yet.