The 'scan' command

Since 1.0 we were given an option to order the SWAT AI to scan a door, meaning you could order them to peek and pie a door then close it, without them taking any further actions afterwards.

However most of the times the 'pie' command is usually greyed out, and I couldn't tell the exact conditions that allow or disallow the said command. Whether the door has been opened before or not, whether the door is locked/unlocked or unknown etc do not seem to have any discernable impact on whether I can use the command or not.

Does anyone know what's up with this command?