Good point about MaxQ, but it was not an important part of my question. What I was surprised is that the Dragon sent a command to the Falcon to shut down the e

Good point about MaxQ, but it was not an important part of my question. What I was surprised is that the Dragon sent a command to the Falcon to shut down the engines. In a catastrophic scenario, it may be that the Falcon does not accept commands and is "stuck" at full throttle. I was expecting them to test ejection while the rocket is at full power without shutting down engines. I guess they do not need to test it that way, they can easily calculate or measure if the acceleration was high enough and by initiating throttle down the capsule minimizes the risk of being hit by rocket debris after it falls apart. In a real life emergency such risks are acceptable, but in a test probably unnecessary.