@netroopia Basically what
@spimmy_x said. If you are downed and finished with 0 kills at the start of the match, you can stick around and hope that your team mates get you good enough placement to gain positive RP. I believe placement RP starts at 13 squads remaining?
I believe how it works, if you are downed and your respawn beacon fully times out, you can then leave the match with no abandonment penalty, if I am thinking correctly. If your beacon has not timed out though, you will still receive negative RP and the abandonment penalty/timeout from playlists. There should be a prompt that you have to acknowledge when you attempt to leave a ranked match, indicating that you will receive abandonment penalty if you leave at that point. If you do not get this message, you should be ok to leave, in theory. If you do leave after that point, you would only miss out on any potential placement RP that your team mates might earn during the remainder of the match.
Also, Bronze rank has no entry RP cost, so as long as you don't leave early and get the abandonment penalty, you will not lose any RP, even if you don't get placement RP or kill points (KP). The entry costs begin with Silver rank.