Might need a bit practice. Easy to miss the jump to the ledge at the end of the staircase (ground level). Do not waste time with sentry guns. Medic after the core is down. Normally only 1 scorpion to deal with, the one guarding the secret passage. Can get it to spawn and then jump back to the ledge. I missed the jump in this attempt and got attacked by the one on the ground floor.
