Why did my dog do this when she died?

This incident happened over 10 years ago but it has been on my mind forever and i want to know from others what to think of it. I loved my old pet Scamper, her life is done today and i miss her dearly, but the night she died over 10 years ago she did something i to this day do not know why she did. The night that she died, we knew she wasn't well because the vet said that she would pass soon, the night that she passed she came to my bedroom door and lied down and died. She was an old mix (small-medium size) who i raised from puppyhood, her life was one of rich memory and many incidents, from car accidents, to being sprayed with a skunk to even protecting us. I don't want to make this into a long obituary about my pets life, but i loved her dearly and i would like to get closure. Do you think she did this because she wanted to be close by? Did she do this for a reason? I've heard dogs go away to die so it seemed odd that she came close. Also in her life she never chewed, bite or barked but that night she chewed through her leash and came upstairs and lied down by my bedroom door and died... Do dogs actually think? Its been bugging me as this would seem to take thinking, and also do dogs know when they are going to die? This is deeply personal to me so please do not write hurtful or mean comments, i'm already hurt enough by her passing and its taking a lot out of me to write this.....