Splicer Key

Source
A Splicer Key can be obtained trough defeating certain Hive in The Plaguelands patrols and Rise Of Iron missions. Defeating a Hive Broodmother or a major Knight will almost certainly drop a Splicer Key

Usage
Splicer Keys can be used at the Archon's Forge for reentry after respawning during the event and can be used at a impassible laser shield's monitor after which you need to defeat some Fallen. These rooms contain one Rise of Iron relic axe and mostly 2 Loot Boxes.