Do not drop your pen cap.
That was one of the first things I was told after entering Changi Women's Prison (CWP).
This is because the entire prison will go into lockdown mode until the cap is found. No matter that it is made of plastic - any object, however innocuous, could be turned into a weapon.
The current CWP (full name: Changi Women's Prison/Drug Rehabilitation Centre) was completed in 1994 as a solution to overcrowding in the old Female Prison near Moon Crescent.
Then, the five four-storey blocks, which could house up to 637 women in 44 dormitories and 177 cells, were lauded as state-of-the-art.
Two decades on, it is still the only women's prison and drug rehabilitation centre in Singapore. But its facilities have been upgraded to accommodate the 1,293 inmates it now houses, and new programmes aimed at reducing re-offending have been introduced.
But some things still remain the same: The 7m-high prison walls that cut off all sound from the outside, the stark concrete floors and walls, and the intense discipline the women are subjected to. There is also a lot of squatting in prison.
As we walked into the yard, a concrete space about the size of two basketball courts, the women immediately squatted when they saw us.
"Good morning ma'am, good morning sir" - they have been taught to greet officers and visitors.
Later on, along the common corridors, red rails about 50cm above the ground are spotted. They look like handrails, but seem far too low for that purpose.
I was later told these are additional support for the women when they are squatting and waiting.
In a squatting position, it takes more effort to get up and move, compared to if one were standing. The squatting is for operational safety, an officer leading us on the visit said.
Looking around the yard, one can almost imagine it to be a multipurpose area in an HDB estate. But in an HDB estate, there would not be grills everywhere.
Nor would there be guards armed with, among others, handcuffs, a nightstick and pepper spray keeping watch over inmates.
And most certainly, no one would be sporting the same short haircut, or dressed in the same white T-shirt and navy blue bermudas.
Then, it was up a few floors to see the prison workshops. Managed by the Singapore Corporation of Rehabilitative Enterprises, these women earn a small amount for their work.
In the embroidery workshop, there were large machines sewing sports badges and name tags.