Like pepper said.
Make two triggers, both on each side. When walking through the front side, you have a trigger_multiple targeting a "game_player_equip". Right infront of the player_equip is a weapon_strip, but it is inactive because on the trigger_multiple targeting the player_equip, you have a killtarget of the weapon_strip. Then, once you pass into the next room, right infront of the weapon_strip, is another trigger_multiple. It targets the weapon_strip, and it has a killtarget of the player_equip (also do this method on the starting point, so if the player passes back through it works).
I know there may be a simplier way using trigger_relys and multimangers (possibily multisources), but since Im at school I cannot try the function out (I cant even assure you that the top method will work :D).