Berjaya Penang Hotel in Georgetown

I strongly feel that hotel guests security could be compromised here, due to blind spots on each of the hotel floors corridor not covered by your CCTV.
On the 31.07.17 at about 10.50 in the morning, my spouse had a bad experience when someone tried to open her door with a key without identifying, immediately after 3 knocks. Luckily the door was latched from inside. The intruder left immediately without a word. When my wife opened the room door to check there was no one and nothing along the hotel floor corridor outside room 2408.
My spouse then inquired from the front desk to find out about the intruder and was told to refer to housekeeping. After room check out around noon, the housekeeper had initially informed my spouse that none of the housekeeping had attempted to enter the room at that time.
Was there a breach of security here? Who had tried to open the hotel room door immediately after 3 knocks without identifying oneself ?? Was it an uninvited guest ???
My spouse requested the housekeeper for an investigation into the incident and a viewing into the CCTV footage. We were sad and shocked to find out later that there was no CCTV footage of the incident as the room was in a blind spot, not in coverage by the hotel CCTV.
I believe this is a serious problem that needed to be looked into by the hotel management. The CCTV footage of the incident could have clearly shown who the intruder was. Possibly, it could NOT have been the housekeeping staff, because the intruder did not identify himself, which i believe is a standard protocol.
Moreover why would housekeeping want to enter the room at that time without request or any service trolley to be seen outside the room corridor?
The above questions are begging to be answered and we will appreciate the Management kind assistance on the matter to avoid future repeated occurrence of the above incident. Thank You.