Armed officers and Army bomb experts rushed to a garda station when a man entered and threatened to detonate a grenade in the early hours of yesterday morning.
The shocking drama happened at Bray Garda Station, in Co Wicklow, when a 24-year-old local resident entered the station at around 2am and approached its front counter.
The individual is understood to have asked officers to lock him up but when this was declined, the man - who is a foreign national - asked to be shot dead. He then left the station but concerned officers followed him.
At this stage, he produced what was believed to have been a viable hand grenade.
Sources have revealed that "one especially brave" unarmed garda, aged in his 30s, spent a "significant amount of time talking the suspect down" as specialist armed back-up was called in.
As this was happening, a decision was made not to evacuate nearby houses, but the closest residents were awoken and told to stay away from their windows in case of a bomb blast.
"This was a very serious security situation for a short period of time, as there were legitimate fears that what the individual had was a genuine explosive device," a source said.
"Gardai at the scene acted in a very calm, compassionate way and managed to keep the young man calm until specialist back-up arrived."
When members of the Armed Support Unit (ASU) arrived, they arrested the suspect and disarmed him of the 'grenade', which turned out not to be a viable device.
However, this was only established after the Army's Explosive Ordnance Disposal (EOD) unit was rushed to the scene under a garda escort and carried out examinations of the device.
A cordon was put in place around Bray Garda Station and this remained in place until the situation was declared safe at around 4am.
The suspect was briefly detained at the garda station before being brought to St Vincent's Hospital in Dublin, where he was being treated yesterday.
A senior source said that gardai are not looking to pursue criminal charges against the man.
"Yes, this was a very scary situation and it did lead to a huge security alert, but this is a man who is not in the right frame of mind," the source said.
"He is a young man that needs urgent and appropriate medical help - in a different scenario, this event could have ended up as a real tragedy.
"Gardai at the scene acted in a calm and compassionate way and all the proper protocols were followed, including the drafting in of the Army.
"The main thing is no one was injured," the source added.