When my PCR test at walgreens come back without a result by wednesday (tested monday) for a thursday cruise, I called Carnival to find out what my last ditch options were. I asked if I could get a test at Smith Cove terminal, I was told no because I needed an appointment and there were no more available appointments for this cruise. I was able to book an appointment that evening at Carbon health for a rapid test, cost $60 each but that was far less than many other pay for options. Drove to southcenter mall for the test, they have a tent set up in the parking lot at the southwest portion of the lot. There were no free options for testing within 100 miles of Seattle, and that had been the case in the previous days as well. I had the appointment at walgreens because I had booked it days early.
We were the only ones there for the test, they ran it while we waited and we had the printout 15 minutes after an MD did the test. I really could have done without the stress of dealing with walgreens, I was told the results would be emailed to us in 48 hours or less. Called several times, told my specimen had been logged but no result available. They would not tell me any info on my son's specimen even being logged because "they can only check on one specimen per phone call." By the time I called back, it was past 5PM Eastern time and they were closed for the day. I never did get any results for either son or me emailed to me. Whether they could have come up with the results on embarkation day when they were open again is possible, but I was glad to have got a printout the day before & it was definitely worth the cost to be free of the uncertainty.
By the way, for those flying in to Seattle for the cruise / staying near the airport, southcenter mall is not far. I don't know if you can get there by light rail, but it shouldn't be a bad fare by ride share.