Through these thick doors, heavily curtained with skins on the inside, it was impossible that any noise or suggestion should come from within to the person who should approach to raise the latch of one of them.

What is the purpose of using strong verb phrases like "heavily curtained," "should approach," and "raise the latch"?
1. to show what the tiger could do
2. to show how easy it was to make a choice
3. to show the difficulty of the choice
4. to show the advanced construction methods