  Panic may spread over a crowd in a similar fashion as contagious diseases do
in social groups. People no exposed to a panic source may express fear,
alerting others of imminent danger. This social mechanism initiates an
evacuation process, while affecting the way people try to escape. We examined
real life situations of panic contagion and reproduced these situations in the
context of the Social Force Model. We arrived to the conclusion that two
evacuation schemes may appear, according to the \textit{stress} of the panic
contagion. Both schemes exhibit different evacuation patterns and are
qualitatively visible in the available real life recordings of crowded events.
We were able to quantify these patterns through topological parameters. We
further investigated how the panic spreading gradually stops if the source of
danger ceases.
