Energy and frames
The energy is frame dependent, and the difference in energy is frame dependent. In changing from speed V1 to V2, the energy change in two frames, one moving at deltaV to the other, with all velocities in a straight line are
V1-squared - V2-squared
and
(V1-deltaV)-squared - (V2-deltaV)-squared.
These differ by 2.(V2-V1).deltaV
As Wizofoz says, the only frame that matters for stopping is the one in which the ambulance is parked. The only one that matters for flying along is the one in which the wind is stationary.