Posthaste (adverb)

1. With great speed, urgency or haste.
2. As quickly as possible, without delay or procrastination.
3. In a rush or with a sense of immediacy.

Origin:

From middle english 'post hast' meaning 'post-haste'.

Examples:

1. The fire department arrived on the scene posthaste and managed to put out the fire before it spread.
2. The doctor instructed the nurse to send the patient to the operating room posthaste, as the condition was critical.
3. The manager asked the team to complete the project posthaste, as the deadline was fast approaching.
4. The athlete trained posthaste in preparation for the Olympic games, hoping to win a gold medal.
5. The ambassador had to leave the country posthaste, as the situation in the region was volatile and unpredictable.