Check carefully

"It's been more than 20 minutes, why haven't you come yet?"
Old K sat in the room waiting.
But after waiting for a long time, there was still no sound coming from the door.
Now, he sensed something was wrong and quickly turned on the intercom to call his accomplice.
"Captain, the third and fourth brothers have already gone up, didn't you see it?" A man's voice came from the microphone.
"Elevator or stairs?"
"I took the stairs."
"Why are you so slow? Even if you have to...