Safari quits by itself, no crash reports show up. How do I make it STOP closing/quitting itself?

Question

Whenever I either close the last Safari window, or leave a few minimized (but not quitting Safari) or play a video in VLC (i.e) Safari seems to have quit itself entirely! I don't get any crash reports or notices about what might have occured, nor any error messages. It is very random, sometimes it just quits when I close the last open window, other times it will close even though I have several windows open, but it mostly seems to be happening when I play videos in fullscreen, and when i exit fullscreen mode Safari has quit itself along with closing all my windows. I've been through the preferences to see if it's been set to behave this way, but I find nothing.
I would really appreciate any help on this, as it is driving me crazy having to start up Safari every time I watch an episode or movie or do anything in fullscreen mode (which, is a pain considering how ridiculously slow it is, with pages not loading, or only half-loading or just seeing that god-awful rainbow-wheel for minutes at a time, and if anybody knows how to solve that last part too, please shout it out!). It even quits itself if I've simply just closed my MBP (not shutting it off), and then when I open it again (whether it is 10 minutes later or 5 hours later) Safari has quit and needs to be restarted/reopened.

Answer 1

The next time you have the problem, note the exact time: hour, minute, second.
If you have more than one user account, these instructions must be carried out as an administrator.
Launch the Console application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Console in the icon grid.
Make sure the title of the Console window is All Messages. If it isn't, select All Messages from the SYSTEM LOG QUERIES menu on the left. If you don't see that menu, select
View ▹ Show Log List
from the menu bar.
Scroll back in the log to the time you noted above. Select any messages timestamped from then until the end of the episode, or until they start to repeat. Copy them to the Clipboard (command-C). Paste into a reply to this message (command-V).
When posting a log extract, be selective. In most cases, a few dozen lines are more than enough.
Please do not indiscriminately dump thousands of lines from the log into this discussion.
Important: Some private information, such as your name, may appear in the log. Anonymize before posting.