import random


def choose_random_elements(_list, num_elements=5000):
    """
    Choose a certain number of elements from given list randomly and return the
    original list without the chosen elements as well as a list of the chosen
    elements.
    :param _list: list with elements to be chosen from
    :param num_elements: number of elements to be chosen
    :return: tuple (original list without elements, list with chosen elements)
    """
    indices = random.sample(range(len(_list)), k=num_elements)
    choices = []
    for index in sorted(indices, reverse=True):
        choices.append(_list.pop(index))
    return _list, choices