to step into, to break into, to get deeply involved in

💡 Nuance & Usage: Can mean literally stepping into a place (e.g., a room, a trap) or figuratively delving deeply into a topic or situation. Often implies entering with force or determination, or getting involved in something complex/difficult. 物理的に場所に入る場合と、ある状況や話題に深く関わる場合の両方に使われます。