It shows I left a game in rapid but I left for 10 secs.

I once left a game for 10 secs in rapid. I thought it was 80 secs.

The time depends, among other things, of your history of game leaving.

@arjyorhik here is the code: github.com/lichess-org/lila/blob/a59856a8167ea9c658a0cb2cac931b6f5ec296fa/modules/round/src/main/RoundSocket.scala#L263

the time is based on time control 40seconds*x
and that time is for the whole game meaning if you disconnect for 5 seconds you loose 5 seconds of your dc time and cant get it back meaning yes you can leave for even a second and loose