What is Rusty Ryan is referring to in this scene?

In the movie Oceans Thirteen, after the drill hit the bank's hotel building for the third time, the drill does not stop at once; it goes on for several seconds and the building vibrates. Then Rusty asks others (maybe he asks himself),

Do you think Roman would.... [pause] Nah.....

Then we see Roman Nagal drinking from a soda/beer can.

What I want to know is, what exactly Rusty was referring to in his dialogue above? I can't think of anything that fit into the plot.