Best Blowout Support Event 2017 until July 04 (Europe) or Aug 23 (USA).  

IAHGames will be including Cadet Adriana character card in an upcoming event. Details are not available yet, but based on the screenshot provided by [CM] Calleigh here, it will be related to Singapore's National (Independence) Day which is on August 09 (Thu). So players can expect it within 1-2 weeks from now...

Meanwhile, there is Jack Space Bounty Hunter Event until August 02, 2012.

Update: The event is now available from July 26 to August 16, 2012. It involved hunting event monsters to collect alphabets to spell "Cadet Adriana", i.e. A x4, C x1, D x2, E x1, I x1, N x1, R x1, T x1... That's a lot of "A"; I hope the drop rate for "A" doesn't suck. See [sGE] Cadet Adriana National Day Event for details.