The gas dispersed too quickly in vacuum to do more than singe an enemy craft's hull, or slightly degrade its sensors.
They're obviously waiting until the gas disperses.
If there are no other forces acting on the gas, then a gas would simply disperse in all directions independent of its relative temperature.
As the gases dispersed, the stars quickly returned to view, and Spock felt reassured- no, not felt, he corrected himself.
Safety gaps have been allowed between modules of process equipment so that gas can disperse quickly in the event of a gas leak.
It was an hour before the gas had dispersed enough to enable him to reach the floor of the chamber again, and breathe the air down there.
The hissing or sizzling had ceased, and the gas had evidently dispersed.
Nasty gases and smoke disperse into the ether; sewage eventually floats out to sea.
Waiting impatiently, Naslin counted down the minutes until the gas could disperse and it would be safe to drive through the area.
When she didn't faint, she knew the gas had dispersed even if its effects remained in force.