Section 41(1)(b) in The Bangalore Metro Railway (General) Rules, 2011
(b)at a location near station control room, a key to a designated emergency eXit shall be provided in a glass box, this key is for use of maintenance staff in the event of emergency during non-traffic hours, the emergency key box shall be inspected each morning by Station Controller and use of the key shall be reported to the Security Controller who shall arrange for the box to be secured again;