I'm not sure why Riff is acting surprised. He's known for a while that Sasha was a fake tinkerer.

I don't get the joke today. Riff gives Sasha a remote that she says she never worked on because the tinkering thing was a ruse. What am I missing?

The remote was an honesty test. If she continued the ruse of being a tinkerer, then he'd know this whole conversation is a set up.

Unfortunately, the opposite isn't true. Just because she came clean about the remote doesn't mean that she isn't still a lying b----*.

*In fact, she pretty much has to be. I really thought she was redeemable somehow until she admitted that she did NOT know that the glass in front of Riff was bulletproof.