dimensional anchor vs dimensional steps

[piquwee]

Hello,
Does a dude with dimensional steps get a shot at side stepping a dimensional anchor beam before it gets to him, or unlike arrows and other range weapons it locks him in place?

[Aspasia de Malagant]

Unless it's quickened and readied against being shot at, I'd say if the beam hits your touch AC, you are locked down like any other hit by the beam.

[piquwee]

So a dimensional step needs to be readied for it to be used by anyone with that arcane spell like ability to pop out of the way of anything?