Before reading this, bear in mind that I only woke up about 20 minutes ago, so I apologise in advance if this makes no sense! :P Ok, I've always understood it that the monsters in SH1 were created from Alessa's nightmares. The monsters in SH2 are created from James' guilt (though I've heard some ppl argue that Mary actually creates them to punish James, which I don't agree with). In SH3, I'm not so sure. It's the game I'm least familiar with, though, if I was to make a stab at it, I'd say they are created by Alessa/Heather. If that's the case, then I'd say the nurses have revolvers to maybe signify Alessa's urgency to stop Heather from giving birth to "God". I know they are the same person, but, let's face it, Heather fights Alessa in the amusement park.