[Centurion2000]

All of us are wondering about the motive. Maybe a terrorist attack like jocon suggests. Perhaps a revenge attack for someone in a gang who was shot or arrested.

Or someone wants some high profile hostages while they demand for a certain terrorist ringleader's release.

[Enterprise]

Do you think they might have been wanting to take a police officer hostage? I would think they would "stalk" someone and take him/her by surprise during a period of vulnerability, but not during an assault on a sub-station where numerous officers may be present and with access to weapons other than their pistols.