Hello and welcome,
Couple of issues with code apparent, you don’t appear to be resetting A Pressed or B Pressed anywhere, so once triggered once they will indeed be locked on.
You are also using outputs from nodes in one event handler as inputs for a node in a different event handler, there are nodes you can share like this (“pure” functions and casts) which you probably don’t know about yet, a set node is not one such and if you are new to this I would just advise to avoid doing it altogether.
Fix those two issues like so, but with D substituted for B where appropriate 
Timelines seem a bit messy here, I think you will have less problems (and a better result) using an RInterpTo or RInterpToConstant node with current rotation and a target rotation.
Whichever way you go, good luck!