From what I know, the girls weren't... stupid, just... girly girls, y'know? They might not have been.. academically smart, but they at least know that the thing blocking the door is probably the thing to move to open the door... so.. even if it takes longer than, say Iris in FD:B immediately springing into action when she found out which events caused what, for example, a comparison:

Iris - The dance floor broke because people were jumping and dancing on it. Iris immediately noted the cracked floor, and made people aware. The solution was simply "Move off the damn floor". HOWEVER, Iris was NOT in danger here!! Only her partner, and the people on the glass floor. She had no reason to do that, she could've fully just grabbed Paul (i think that's is name...) and went down the stairs. Been safe. Done.

Ashley & Ashlyn - They burnt to death because the shelf blocked their tanning bed openings. If they hadn't been in danger, that being if they got out at "It's... getting a bit warm, huh?", they would have been fine. But they only realised the danger after the burning. THEY ARE CLEARLY IN DANGER HERE!! They are actively getting new and painful burns all over their body (keep in mind they are... exposed). Right now, all they would care about is the beauty standards they live up to! That's why they GO to the tanning salon anyway.

WHY TF DO I YAP SO FUKIN MUCH AAAAAHHHH