Lupin's transformation/moon timing

[cassandraclaire73 at yahoo.com]

No: HPFGUIDX 2837


I agree with Blaise...it's a plot hole and it's driving me nuts as 
well. I was trying to work Lupin into a story I was writing, and ran 
smack up against this problem. To my mind it's a discrepancy on the 
level of the whole Priori-Incantatem-James-and-Lily-wand-order thing.
If Lupin only transforms when the moonlight touches him, why doesn't 
he just stay the heck inside? If he transforms at every full moon no 
matter where he is, then he would have already transformed before 
coming out of the tunnel with Harry and the others. Aaargh.