Probably fucked either way. The bear would be painful, but the spiders might give you a chance if you don't bother them and stand perfectly still for an hour. But if you still get bit, you can die in that painful and prolonged way. You could probably try to smash the black widows too, if you want to go out as a mass murderer of spiders, rather than go out as a knob killed by a bear in one swipe.