player no longer gets hurt on hallway reentry

this fixes jhoff's first problem in https://github.com/kyleconroy/hawkthorne-journey/pull/573#issuecomment-10399586

which is http://www.youtube.com/watch?v=W2eRZrNb39I&list=UUkqNQ_aRqOBjFbE_b368i5w#t=2m29s