Dumb question: did he ditch his car and get a rideshare?
Good question. IDK.
If the man seen in the aquatic park video was him, then he must have walked away. LE doesn't say that they saw him get back in his car to drive away or that he walked out of the maintenance area and down the street. IIRC, they presumed he had walked into the woods surrounding the maintenance area because they spent several days searching the woods, etc. around that area for several days. It was a big search. If he had walked away from the car to catch a ride share, one would think the dogs would have picked up his scent adjacent to the maintenance area.
We also have to assume that the video tape of the maintenance lot continued after the man left the Dr's car and that it showed no other kind of activity until LE discovered it.