code: function( data ){
  
              var self = this
                  ,col
                  ,collisions = data.collisions// Physics.util.shuffle(data.collisions)
                  ,i,l,b
                  ;
  
              for ( i = 0, l = collisions.length; i < l; ++i ){
  
                  col = collisions[ i ];
                  // add bodies to list for later
                  this._pushUniq( col.bodyA );
                  this._pushUniq( col.bodyB );
                  // ensure they have mtv stat vectors
                  col.bodyA._mtvTotal = col.bodyA._mtvTotal || new Physics.vector();
                  col.bodyB._mtvTotal = col.bodyB._mtvTotal || new Physics.vector();
                  col.bodyA._oldmtvTotal = col.bodyA._oldmtvTotal || new Physics.vector();
                  col.bodyB._oldmtvTotal = col.bodyB._oldmtvTotal || new Physics.vector();
  
                  self.collideBodies(
                      col.bodyA,
                      col.bodyB,
                      col.norm,
                      col.pos,
                      col.mtv,
                      col.collidedPreviously
                  );
              }
  
              // apply mtv vectors from the average mtv vector
              for ( i = 0, l = this._bodyList.length; i < l; ++i ){
                  b = this._bodyList.pop();
                  // clampMTV( b._oldmtvTotal, b._mtvTotal, b._mtvTotal );
  
                  if ( b._mtvTotal.normSq() < this.options.mtvThreshold ){
                      b._mtvTotal.mult( this.options.bodyExtractDropoff );
                  } else if ( this.options.forceWakeupAboveOverlapThreshold ) {
                      // wake up bodies if necessary
                      b.sleep( false );
                  }
  
                  b.state.pos.vadd( b._mtvTotal );
                  b.state.old.pos.vadd( b._mtvTotal );
                  b._oldmtvTotal.swap( b._mtvTotal );
                  b._mtvTotal.zero();
              }
          }
docs: internal
  BodyImpulseResponseBehavior#respond( data )
  - data (Object): event data
  
  Event callback to respond to collision data.