High Intensity Action music is designed to create a lot of surprises, shocks and quick rush of emotions. The tension is high and there's a constant sense of uncertainty. 

John Powell's "Bourne Ultimatum" - 5M16 Tangier Bike Race (measures 71-78)

Rhythm: 

• Tempi range from 112 BPM to 168BPM with fast sub-divisions.
• It's common to use odd meters (5/4 - 7/8) and/or use syncopations with displaced accents.
• Unpredictable metric changes
• Hits

Harmony:

• Dissonances are very common. 
• Tritons and Minor Seconds are very common
• Use of non conventional scales
• Fast modulations and chord changes

Tritonic harmonic sequence

Melody:  

• If present, melodies are more fragmented than anything else
• Often use non conventional scales/modes

In our example, John Powell uses the Phrygian b4 mode in Bourne Ultimatum.

Phrygian b4

The scene follow a chase in the street of Tangier (Morocco). This mode is the closest 'tempered' scale we have to a traditional 'microtonal' Arabic scale called Maqam Huzam. This is a great choice to bring us to this exotic location. 

Orchestration:  

• It requires a large instrumentation
• Ostinatos and repeated figures are generally placed in the upper strings (Vl1, Vl2, Vla and/or Cello)
• Accents can be added with Brass and/or Percussions
• Woodwinds are commonly used to create fast runs, either as incidental elements or as a part of the background to add movement
• Bass lines are spread across the bass of the whole families (Woodwinds, Brass, Strings, Percussions)