El-cheapo all-in-one-piece shower ("box"/cubicle, floor, door, etc)

Got screwdriver to undo the drain-cover -- way too shallow for
my (actually, *any*) screwdriver; seems that it's yet another
el-fako (like that bathroom air-vent/blower I mentioned once,
that simply blew it right back out into the room!).

That is, those indentations that *looked* like the heads
of screws, wereen't. Were simply indentations!


How to snake it?

Thanks,

David