where to find server-downloaded maps?

[Admiral Metal Giant]

So there was a medic vs engineer server I joined and on one of the maps it has this door that was labeled VIP with a 3x3 set of squares that I assumed was a keypad. To figure out how to get in, I loaded up hammer and tried to find the map (it was called zs viaduct) and look at the "button" inputs/outputs but I couldn't figure out where it saved when I joined. (No, it's not in tf/maps)
Can someone help me find in which directory the map downloaded?

 

[Necrσ]

The map should be under tf/download/maps (not tf/downloads), as this is where maps downloaded from servers are stored.
You also mentioned you want to open the map in hammer, which in that case you will need to decompile the map with a program like BSPSource

 

[Da Spud Lord]

Look in tf/download/maps.