A PETROL can is flung at ERU officers during a hostage situation. This may be an exercise but they are preparing for the real thing.
The Herald can exclusively reveal pictures of the garda drama at a secret site on the outskirts of Dublin city.
It was run in conjunction with colleagues from outside police forces who were there to observe and act as hostages and hostage-takers.
In this situation, an alarm has been activated at a disused hospital and attempts to contact the security guard at the site have been fruitless.
Local gardai respond. A cap is found on the ground and suddenly the uniformed gardai are confronted by a man with a knife, there is a smell of petrol and the security man is being held. A hostage situation has begun and the various arms of the gardai needed spring into action.
A mobile command centre arrives along with the Garda Negotiation Unit, officers from the Regional Support Unit (RSU) secure a cordon around the area and the Garda technical Unit sets up audiovisual equipment to give the on-scene commander eyes and ears on the situation.
Little is known of the hostage - at this stage, it's thought there's just one - and his captor or captors. Communication has been established and the names of those involved become known.
A tactical team from the Emergency Response Unit (ERU) arrives, but sets up out of sight so as not to spook the hostage-taker.
An observer/marksman sets up and, having a clear view of the door, he establishes that a third man is inside the building, that there is a petrol can present and the man carrying the knife has matches. The plot thickens.
Gardai on the scene with responsibility for gathering intelligence have established that the man wielding the knife made an allegation of sexual assault when he was 16 against the third man, and the security guard is merely an innocent victim. The man accused of the sexual assault is now the father of two young children.
All of the information which is gleaned by the ERU, the technical team, negotiators and intelligence officers, is relayed to the commander who has ultimate responsibility and control over the situation.
All ERU plans are documented for the commander and must be signed off before any movements are made.
Garda negotiators, who this exercise is primarily aimed at, facilitate the handover of a phone to the hostage-taker.
The ERU is charged with delivering the phone, and an armoured vehicle is used to provide ballistic cover before the men crowd behind a shield and edge towards the door.
Garda negotiators have agreed that the hostage-taker will stand away from the door while the exchange takes place.
The ERU observer/marksman is making sure that he is true to his word.
Suddenly the door swings open and a petrol can is flung. The ERU team retreats slowly never taking their eyes off the hostage taker, the team leader directing things.
It is the most dramatic moment of the day, the negotiators successfully defuse the situation and there is no need for an armed intervention.
A member of the Garda Negotiation Unit who was coordinated the negotiating effort, later outlined their tactics.
"We adopt a softly-softly approach. The info we have been given is that it has been a burglary gone wrong but we have to find out more information," he said.
"Obviously our first priority is the preservation of life and the safety of the hostage.
"The aim is to keep them talking and try to find out what has sparked them off.
"We then try to de-escalate the aggression, lower emotions and raise their rational thinking. Our aim is to build up a rapport with the hostage-takers."
Many of the Garda Negotiating Unit are trained externally in psychology and liaise with the Dundrum Central Mental Hospital if their expertise is needed.
A senior ERU officer explained that the training exercise, procedures and equipment used in these exercises are designed to simulate a barricade incident, where there may be no hostage, but the subject may present a danger to himself, the police and the public if the situation is not contained and dealt with effectively.
"In this case the ERU has been called to respond to an incident and a tactical team is en route," he said.
"Members of the unit are involved in the gathering of real-time intelligence through physical (observers/observation) and electronic means.
"There is generally discreet deployment of armed ERU personnel at critical incidents until the on-scene commander decides that they are required -- they should be largely invisible, where practicable, until they are required to act.
"If the situation goes on for a protracted period of time, the ERU will document plans for an intervention and go through them with the on-scene commander, who must sign off on them.
"This kind of scenario-based training outside of a controlled environment is extremely beneficial to all involved.
"This training allows for interaction between a range of garda units and it's good that these people get to know each other and work together."
An Garda Siochana and the ERU constantly monitor world events and international law enforcement incidents and develop strategies, procedures and tactics to deal effectively with whatever type of incident occurs in this jurisdiction.
"It is important to be prepared for all eventualities," the officer added.
The assistance of all the officers involved in the incident is important. A member of the Garda technical team told the Herald that information was essential for the commander on the scene to make the most informed decision possible.
"The technical support unit plays a peripheral role but it is also vital," he said.
"We try and provide audiovisual feeds from the scene which will assist the on-scene commander in his work. In these situations knowledge is power."