Slipping Past( Complete Scoundrel, p. 89)
[Movement, Skill Trick]
You can slip through a tight space without breaking stride.
Escape Artist 5 ranks, Tumble 5 ranks,
As a swift action, you can ignore the additional movement movement cost and penalty on attack rolls and to AC when squeezing through a narrow space (PH 148). The benefit lasts until the start of your next turn.