I was looking at enemies to attack while waiting for the next wave. I had added my maxed grimm and nothing else when i was distracted and had to reach over my tablet. I look back at the screen and I’m in a battle. With only 1 hero. The sleeve of my shirt probably grazed the screen.
My suggestion is this:
Add a confirmation box for starting a hit when an entire team has not been selected yet.
This should minimize the damage these situations can cause.