Hi,
I believe the old buildings outside commando camp are the property of SAF, and I noticed that they are sometimes patrolled by soldiers. I'm not sure if it's part of their guard duty but then I guess we may not know (perhaps classified?)
An officer from the camp told me I can't shoot photos there, and took down my identity card number. He also assumed that I should know that the buildings are property of SAF, and so no photography is allowed.
As with old Changi Hospital, the previous Malay caretaker was more lenient with explorers. It appears that he's been replaced by a tanned Chinese who's less tolerant.
I was discovered by the Chinese man, and he told me off rather untactfully (like most S'porean security guards are) that photography isn't allowed, and said he would call the police if I continued/remained. Ironically, I didn't see the "No trespassing" or "No photography" sign anywhere.
I have seen images of shoots done there but I'm unsure if those photographers encountered any problems.
Those who wish to go might want to practise stealth and caution.