What PC767 describes has happened before on other types ( slide falling out, fortunately not inflating).
Not familiar with the 380 so willing to shut up PDQ but..D1R - on at least two other BA wide body types I'm familiar with 1R is certainly routinely opened and used for catering team access (usually opened from outside; sometimes opened from inside) and/or opened for High lifts (wheel chairs). Out of interest not so on the 380?