Thankfully it seems that Madoka at least doesn't full on fall. She does definitely slip, and trips a little, but - maybe with the help of that arm being there, warding her from falling - she manages to upright herself again at the last minute.

The look in her eyes is definitely panicked though, like she just saw her life flash before her eyes in that instant.

.. and it only turns more surprised when she glances to the side and sees Piccolo right there.

"A--Ah, m.. mister Piccolo! I.. I'm sorry, I.. I slipped.." As if that's something she has to apologize for...