The light allowed you to see the mirrors shine in the darkness. Those guided the path. But also attracted the beast, hence the heartbeat. Though the result wasnt 100% percent consistent :D.
And yes Holena not awaking is a case of a bad trigger, you can sneak to her if you try. We hoped nobody would notice and accidently wake her up correctly. :D
Btw Holena is also a guy with a towel on his head.