I have a loose crown that I can pull half way out. Should I pull out before I can get to dentist or keep rinsing/push back down?

It is better to leave it in to maintain the position of the opposing teeth
and adjacent teeth. This is especially
true if your dentist appointment is more than a couple of days away. My only concern about leaving the crown in is
that it may dislodge while eating or sleeping and you could swallow the
crown. While you can use an over the
counter temporary cement, not everyone has the dexterity to put the cement in
the crown, and the crown in the mouth, and then clean the excess cement before
it hardens. The best option is to get to
a dentist as soon as possible and have it properly cemented.

get to dentist asap  my concern is it coming out during eating and you may swallow it  or worse case aspirate it 

If the crown cannot be pulled out fully with ease, then I would normally recommend keeping it in place until your dentist can evaluate your options.  If the crown loosens any further, take it out completely and use a temporary cement to put it back into place.