var senti_same = ["20150803T170236_20160825T061733_T15SXD",
                  "20150803T170231_20160520T064257_T15SXD"]
var senti2 = ee.ImageCollection("COPERNICUS/S2").
    filter(ee.Filter.inList("system:index", senti_same))

print(senti2)

var senti2_list = senti2.toList(2);

print(ee.Date(ee.Image(senti2_list.get(0)).get("system:time_start")))
print(ee.Date(ee.Image(senti2_list.get(1)).get("system:time_start")))


// map
Map.setCenter(-91.1625, 39.2862, 9)
Map.addLayer(ee.Image(senti2_list.get(0)),
             {bands: ["B4", "B3", "B2"], max: 255*10}, "image 2")
Map.addLayer(ee.Image(senti2_list.get(1)),
             {bands: ["B4", "B3", "B2"], max: 255*10}, "image 2")