"Pancaek or whatever your name is, do I permission to enter the building and explore?"
If permission is granted, break down the barricade (by hand/knife is preferred, monoatomic machete if needed) and let my team in. Sweep and secure the first floor, looking for clues as to what might have happened.
Well, annoyingly, no one seems to have granted you permission to do anything. Drat.
:No anomalous effects on the window. Whatever froze these people doesn't seem to be affecting specific areas. Or does so at random.:
Are there any thermal signatures in the hallway outside this room? If no, or they're far enough away that I wouldn't be closer than the safety range, shove that barricade out of the way with my MkIII exoskeleton strength, then enter the hallway. Unless the barricade is on the other side of the door, in which case open the door/laser it off its hinges and push my way through the barricade on the other side.
You look around...There are thermal signatures on this floor, but none of them are within the 20 foot limit. You knock aside the barricade and shoulder the door open; it had swollen to the point of not easily swinging open. The hall itself is much less deteriorated; thick with dust and quite cold, but not filled with snow or leaves. It's quite dark within the building, the only light coming from the room you just bashed your way out of, and from another window further down the hall. Everything is deathly quiet. You do another quick look around and notice that the heat signatures have moved. They've moved inward, toward you. They're not moving now but, they're definitely in different positions then when you looked the first time.
"Use yer hands, it's less likely to set the roof on fire. Hrmmm... ya said the people were near freezing, right? What if we tried ta warm them up?"
Sweep the snow off the hatch with my hands, then examine it. Check the temperature of my braincase, and compare it against it's temperature when we were outside the dome.
You, rather then using a goddamn rocket to shovel snow, sensibly use your hands to brush the thick coating of white off the hatch. The hatch itself is glass, like a skylight, with a metal handle on side and stairs visibly leading down inside. You don't see anyone down where the stairs lead, and the other members of your group tell you there are no heat signatures near it. The hatch, however, appears to be either locked or frozen shut.
Your braincase is the same temp it was before and always is.