Is there a way to refactor four nested .forEach to change property?

Question

Example:

public disciplines: BrowserDiscipline[] = [];

onAggregateSelect = (event) => {
this.disciplines.forEach(disc => {
  disc.models.forEach(model => {
    model.BDS_Classes.forEach(bdsClass => {
      bdsClass.isSelected = false;
      bdsClass.elements.forEach(el => el.isSelected = false);
    });
  });
});

How bad is it, if I can have over 15 000 elements from all disciplines? Interface of disciplines are below (I removed optional keys).

export interface BrowserDiscipline {
  models: BrowserModel[];
  isSelected: boolean;
}

export interface BrowserModel {
  BDS_Classes: BrowserBDSClass[];
  elements: BrowserElement[];
  isSelected: boolean;
}

export interface BrowserBDSClass {
  elements: BrowserElement[];
  isSelected: boolean;
}

export interface BrowserElement {
  isSelected: boolean;
}