Change the message for branchporting to something other than “You are surrounded by a shimmering sphere”, which sounds more like some sort of protection spell.

When a monster or the player levelports or branchports, it leaves a magic portal behind which lasts for 5 turns. Other creatures can enter this portal to appear on the same level in the same spot as the initial creature did. The portal is probably one-way, and can’t take you back to the original spot.

If you escape the Black Market by branchporting, One-eyed Sam will pursue you on the ascension run.