In the past, the gas just escaped into the air.

In less than ten seconds all the gas had escaped.

In this case, the gas will eventually escape into the atmosphere.

This is because the gases do not escape as fast.

I could hear gases escaping from some of the bodies.

You have to let the gases escape while keeping dust out.

Could gas have escaped from the rocket before it was sealed?

If the gas escapes over time, that friction is reduced.

There came a loud hissing sound, as though gas was escaping.

The open cylinder allows gases to escape, thus making some noise.