Building lift is out for ten days, we're on the eighth floor, and the 2 month old has a clinic visit Friday

The association says a part is coming from Chennai. Until then it's eight floors of stairs, which I can do, and which my father, who is with us this week, should not be doing at all. The baby is the part I haven't worked out. Carrier or arms on the stairs? The carrier frees my hands for the railing, but he hates being strapped in for more than a few minutes and it's 38 degrees in the stairwell by noon 😅 Or do we just stay in for ten days and move his visit? Anyone done stairs with a newborn for a stretch like this?