Add new FAQ item

docs/FAQs/README.md

@@ -1,6 +1,7 @@
 ## Frequently Asked Questions
 
 1. [How can I Inspect app-db?](Inspecting-app-db.md)
+2. [How can I use a subscription in an Event Handler](UseASubscriptionInAnEventHandler.md)
 2. [How do I use logging method X](Logging.md)
 3. [Dispatched Events Are Null](Null-Dispatched-Events.md)
 4. [Why implement re-frame in `.cljc` files](Why-CLJC.md)

docs/FAQs/UseASubscriptionInAnEventHandler.md

@@ -0,0 +1,19 @@
+### Question
+
+How do I access the value of a subscription from inside an event handler? 
+
+### Short Answer
+
+You shouldn't.
+
+Philosophically: subscriptions are designed to deliver "a stream" of new values 
+over time. Within an event handler, we only need a one off value.
+ 
+Operationally: you'll end up with a memory leak.  
+  
+### Longer Answer
+
+
+
+
+