I know I was stunned because it said "stunned" in the left-hand status pane.
I then read a scroll of phase door to escape...
(with mixed success: it dumped me in a room with two more skeletons)
Excerpted stdout:
[LOG] A alarm rings!
[LOG] Skeleton warrior appears out of the thin air!
[LOG] Thief activates Stealth.
[LOG] Thief appears out of the thin air!
[LOG] Skeleton warrior uses Stunning Blow.
[LOG] Skeleton warrior hits Greenleaf for #aaaaaa#88.68 physical damage#LAST#.
[LOG] Greenleaf is stunned!
addTmpVal stunned 1 :=: 0 779
Effect duration reduction < 2.3
Effect duration reduction > 1.3
checkHit 10 6
=> chance to hit 64.612803567824
[LOG] You have found a trap (trap)!
[Identify] scroll of phase door true
[LOG] You have #FFFFFF#11 #UID:387:0#scroll of phase door#LAST#.
[LOG] Skeleton mage casts Flame.
[LOG] Skeleton mage casts Manathrust.
[LOG] Skeleton mage hits Greenleaf for #PURPLE#122.25 arcane damage#LAST#.
[LOG] Skeleton mage hits Greenleaf for #LIGHT_RED#16.72 fire damage#LAST#.
[LOG] Greenleaf is not stunned anymore.