Deathstroke is doing the fingers to the nose meditation thingy. That means he's tuning his senses so he can hear the heartbeats of his opponents and the flutter of a butterfly's wings in Nicaragua.
Whoa! Ninja slide step. Nice maneuver, Deathstroke. And Cassandra Cain is arse over heels, kids. I cannot say that I've been following this Batgirl's career in the DCU but I don't think she would make a rookie mistake like that. Must be the drugs in her.
From Teen Titans vol. 7: Titans East trade paperback.