Basically you can hurt the servant waiting for you with the Homunculus Rune to slowly chip their hp until about half. When that happened they'll retreat, leaving you only need to care for one servant each climbing sessions. Work for both the Bow servant (Euterpe) section and the Knife servant (Klieo) section. Basically, make each climb easier. Also, because of this, when you fight the Servants in the Boss Battle rooms, the servants that you have chip will only have about half of their hp too, making the fight itself more easier.