Play mission with alt 0 in auto mode

Hello.

my drone take off on the hill.
mission waypoints’s altitude is lower than take off altitude.

below is my waypoint.

35.8508276,127.1230727,15
35.8474597,127.1226009,15
35.8474597,127.1226009,0 ← this is problem.

altitude 0 is ignored then mission is over.
How can I play the mission with lower than take off altitude?