They were definitely intimate before he died I’m pretty sure it’s mentioned in chapter 11 where the mc mentioned that he didn’t do enough guiding for the ml I guess they have be intimate to guide their esper not sure tho it’s a common in the guide/esper trope
It was a dream, if you read carefully, he mentions in it that he. 1, died and came back to life, 2. Their age gap before he died. And 3. Forgot seme's age when clearly, the seme of that scene is current version(based on the scar)
no back when he was in his original body he has never done guiding beyond kissing, and even that happened only twice
It wasn't properly explained in the manhwa but he often let himself be punched in that body bcs: 1. Sergeant Kang Hajeong's body is too weak (he's slowly trying to get in shape w/ the help of Han byeongeun), 2. He will use it as evidence to report the abuse; he has done this before to the Esper from the team he used to belong although not shown in the manhwa (this happened when he was admitted to the hospital).
Also, yeah it's a dream; he suspects it's bcs he made contact with Kim Muhyeok's wavelength before
hope that was only a dream and they weren't that intimate before he died. also why must we turn a sergeant into a damsel in distress who needs saving from a punch?