No they can't survive a single lung hit as every breath will be tainted with blood and cause them to drown in it. They can survive awhile but not days and yes they can get back up and move if bumped. I would say he missed the vitals completely as even with a nick he won't make be still running after a night of setting up. The labored breath sounds good indicate a neck shot or even a missing jaw, they can live a long time and the blood can havebubbled appearence to it. The only way to know for sure is find the deer unfortunately.