Distribution of ARGUS and Medusa sources used in this work overlaid on an F555W HST-WFC3 image. ARGUS stars in which no variability was detected are shown with blue circles, ARGUS variable stars are represented by red squares, and ARGUS stars with too low S/N for RV analysis or no suitable absorption lines are indicated by red crosses. The ARGUS IFU pointings (A1 to A5) are also shown as grey transparent rectangles. Medusa non-variable stars added to the sample are represented by green diamonds. The dashed circles indicate projected radial distances of 2, 4, 6, and 8 pc from the centre of R136.