gamay pa ko nakakita na ko sa TV series sa SWAT (starring Steve Forrest and his gang of snipers). One of the tactics they portrayed in the show is to shoot the tear gas before the assault starts.
The latest account of Inquirer.net indicates that they hit hard the window glass first with their maso, but then was forced to wait for another hour until they used the tear gas and the hostage taker shot in the head by a sniper, presumably by a member of a SWAT team.
Ngano man tawon nga wa man nila banati una ug tear gas to at least minimize the vision of those inside the bus. Ila pa man dyud gi maso and that of course made the hostage taker more agitated.