I was seconding 'Open the Box - VS 4b' at Staden on 31/07/2020 and had a very narrow escape when I dislodged a 'head-sized' block, just as I was after stepping away to safety from the top-out. The rock had shown no signs of being loose and had been 'apparently' well embedded in the lip of the top out - but wasn't used as part of the climbing by either the lead or I. The rock landed at the the start of the climb, fortunately about a foot from where a couple of our party (including my 12yr old) were getting kitted up. Luckily, they'd responded to my frantic shouts of 'bellow'. A very fortunate near miss!