Be a Spy or Be Killed
One reason you would not want to have been a spy is rigorous training. There is a lot of training you have to go through before you’re a spy. Something’s you have to go through are parachuting, running, rope work, and plastic explosives (12-13). You also have to know how to handle your bag of tricks. This helps you be a spy. They teach you how to kill someone when shaking their hand. “Shake the persons hand, twist their hand then stab them with a knife” (18). Without training you would not know what to do.
Another reason is being captured. If you are captured Germans will want to get info out of you (11). They could also just kill you. So you should give them info if you want to live. “If Germans arrest you, you will be killed”. They could also find you if you parachuted into their land (14). You would want to know how to pick a lock or to or know someone that will sneak you out (16).
Being a good actor to blend
The last reason is being a good actor so you blend in. Blending in to civilians when Germans are around will help you plant bombs all around Germans. Also you can figure out what the Germans are planning to do (22-23).If you get caught you will most likely be killed. You can also fill your pockets with garlic to keep dogs away (27). You would only need to do this if you messed up big time.