Okay, I spy two things:
1: This titan that they’re attacking, you can clearly see that it’s rather more proportional than any other typical titan, considering they have an entire squad attacking it. Usually, it’s one small group, but they have 5. Could it be special titan, maybe the last one?
2: Secondly, that guy kinda looks like Eren, also something that Eren would more likely say. Not to mention this is before him waking up under the tree. The timeline theories that everyone made up could really piece together, maybe this is how Eren "died"