The Hurt's is The Key

They were talking to Samus, U-MOS and Mother Brwin and they disappear, they left the Room and saw three Black Coated Person

????: So Boys how was your time with- who was it again?

Gumdramon: We don't remember anything at all. But you already knew that, haven't you?

???? 2: You look pretty calm. Guess you decided they weren't worth stressing over. Out of sight, out of mind, right?

Shoutmon: That's not right.

??? 2: Hm?

Shoutmon: It just like you said; everyone we met we can't remember. But still, we're angry that we've forgotten them. We feel a moments of loneliness.

Damemon: You said there would be no hard feelings, but we were Hurt. When the memories are gone, they just leave whole. And having that longing inside me hurts. But it'll help me, somewhere down the road. It's they're key we'll need to unlock all my memories.

??? 3:... You are right.

They disappeared