1. What does it mean?
탈주 literally suggests escape. In online games it means leaving a match before it ends, often abandoning teammates. In casual everyday speech people also use it jokingly for wanting to get out of an unpleasant task or gathering.
Also written or said as talju
2. The nuance
A disconnect is not automatically intentional. Do not infer someone's motive from their absence, and distinguish a joke about leaving from actual disruption.
3. Examples
“한 명이 탈주해서 남은 팀이 힘들어졌어.”
One player left the match, making it harder for the remaining team.
“탈주인 줄 알았는데 인터넷이 끊긴 거래.”
We thought they had quit, but apparently their internet went down.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.