I was confused between S2 and S3. If you have access to unlimit buyable picks, then yes, buying it to pick on that place is the fastest, cheapest way to train. If not, and have access to unlimited grenades by way of random encounters, then yes, trapping doors and windows there is a good way to train ENG.
I remember that the english size2 grenades are good to train, because its damage is small, unlike the size4 types, especially the pineapples. Mhmmm That probbably S2.
You need the coded message from the Penemünde Archives mission, speak to the THO Agent after capturing him at the Finnish border and then get the code book in the Switzerland covert mission. It should activate a Poland mission zone.
Or you can cheat
To cheat, open the file s3autoexec.cfg, add the "wirbelwind" without quote to
the end of it. that will allow you to use ~ to pull down console. type EXACTLY
ScenarioAddVisibleZone( "Secret" )
that to make visible the mission zone in poland
BeginZone( "Secret" )
that to begin the zone.
space and capitalization must be exactly as above, mind you.
That robot is impossible to do stealth missions, so you should not cheat your way in too early. Only engineer (ENG 130+) can activate the robot, so yeah, currently you have no worry on that account~
The mission got some robots like last mission Assault, so if the mod remove them, possibly we get an empty factory~