Usually with adaptation, you want to replicate the most important scenes from the source material in to a different form of media. The audience wouldn't like it when their favorite series has some changes done with the adaptation However, a series like Devil Survivor 2 that has scenes where a character could possibly die can make for interesting experiments with the media. Basically, anything can happen with this show and that happened in episode 3. A character died. It was unexpected because in my play through of DS2, I was able to save my crew of summoners to fight another day (Or grind another day :D). The purpose of the death footage is to make you manage your time in order to save your crew from certain death. However, the show is using the system to make for a less predicable scenarios and has the audience on edge as to what will happen later on. This also reinforces the fact that Hibiki isn't all that strong after so far being able to handle most situations up till now. I expect that he'll be rethinking his role in this dangerous world him and his friends are now facing.
On another note, the show introduces the auction system where the gang can get new demons and Daichi has already shown that it important to pick the right demons and not get a lot of them. I'm curious to see if the character will ever use attack abilities of their own instead of having their demons doing all of the fighting. I mean, Io wouldn't have gotten grabbed if she could just throw some lighting on Botis and support Ogre.