Yeah if a roundabout is small - single lane, 2-3 exits, 10m or less in diameter - you can get away with doing this (indicating your final direction).

Once they get bigger - bigger diameter, multiple lanes, more exits - its safer to indicate your intention to enter and exit the roundabout.

Mega Time Squad (https://m.imdb.com/title/tt5758726/?ref_=ext_shr_lnk)

No spoilers just watch.