Possible Clues:

• Look surreptitiously, like Tom
• Furtive glance
• A palindromic glimpse
• Word with hole or show
• One might look a little likethis, Bo
• Budding twitter
• Look slyly
• Something in 11 across would have this sort of a look while looking for the flock
• Furtively look both ways
• Can't hear one when the audience is gripped