Before

• A lower-level NPC joins the party
• Framing someone else
• Shouldn't be seen by someone
• Tasked with retrieving something
• The weather affects the combat
• There is a hostage situation

During

• A surprising mechanic
• Another wave of minions show up
• Bets on the outcome
• Low stakes (fighting ring, etc)
• More than two parties with varying motives
• Natural timer (flooding chamber, etc)
• Some creatures surrender and other don't, or surrender and then backstab
• Stronger creatures that are already damaged
• The terrain changes
• There is a hidden escape route

After

• Booby trapped treasure
• Dangerous terrain
• Lingering effects (disease, exhaustion, etc)
• Injured NPC(s)
• Noise drew more monsters
• One piece of a multi-piece treasure
• Responsible for damages and/or cleanup
• Rush into next fight
• Timer to get somewhere