The military told all non-US citizens to stay together for safety, Ms Sachs added.
They later told them they would be secretly smuggled out in groups of 10 under cover of darkness as it had become too dangerous for them to remain in the stadium, she told BBC News.
"When we were leaving, people were going 'Where are you going?' and giving us looks.
"But the military got us out, which we were all thankful for."