  We consider a crowd of N persons trying to exit some area trough a small
exit. The probability is calculated that an individual is able to withdraw from
the crowd under one's own steam. The problem is simulated within the
generalized force model (D. Helbing et al., Nature 407 (2000) 487), and all
model parameters are taken from this paper. The results indicate, that in a
crowd of 150 persons, this probability is not greater than ten percent. We also
evaluate the number of helpers necessary to get the above probability of fifty
percent.
