The trouble with Thin Places

OK, we've got a real problem here. Hnaef tried walking across the Thin Place in steel toe-capped boots after a hard day at the wholesaler's. Unfortunately the steel in the boots reacted badly with the astral dimension, and he's fallen right through. Can all Beaker Folk please stay the safe side of the red-and-white tape, while we try to work out how to pull him back.