Not sure.
its iffy wrote:
irunfar is calling the results iffy, although he has won that race 6 times now so that is surely something solid. I also found he's run a marathon @ 2:33 (per 2019 article linked below) and owns a course record for an alaskan ultra (40 miles in 5:36) so he's definitely a solid runner but that looks like a stretch. would not be surprised if the course had a small change or something that threw off the distance
Tunnel marathon is a pure downhill course,about 2000ft I think so is no way reflective of a proper marathon time so no way he replicates that in a 50.