Final answer:
When de-icing, priority should be given to critical safety surfaces like roadways and aircraft control surfaces using freezing point depression methods, as pressure alone is insufficient for melting ice.
Step-by-step explanation:
The procedure you described does not provide sufficient context to determine which surface should be de-iced first. However, in general practice, when de-icing, priority typically goes to surfaces where safety is critical. For instance, freezing point depression is used to remove ice from roadways and the control surfaces of aircraft. This is because ensuring these surfaces are ice-free is essential for safe driving conditions and aircraft operation, respectively. The pressure exerted by vehicles or the aircraft itself does not sufficiently decrease the melting point of ice to de-ice these surfaces. Instead, melting is facilitated by the application of substances that lower the freezing point of water or through mechanical means. Likewise, in the physics of skating, it's understood that friction and a thin layer of water on the ice contributes to the ease of gliding, rather than pressure-induced melting. Therefore, when considering de-icing any surface, it is crucial to evaluate the importance of that surface in relation to safety and function.