[Scenario]

It took me 30 seconds to do this...

pawn Код:

new
    KillStreak[MAX_PLAYERS];

public OnPlayerDeath(playerid, killerid, reason)
{
    if(killerid != INVALID_PLAYER_ID) KillStreak[killerid]++;
    else KillStreak[playerid] = 0;
    
    switch(KillStreak[killerid])
    {
        case 3: // do something, they have 3 kills
        case 7: // do something, they have 7 kills
        case 10: // do something, they have 10 kills
        case 20: // do something, they have 20 kills
    }
    return 1;
}