Evade (dodge) - left Ctrl key.
Get up (after "dizzy" state, that purple line above the character head, passed off and prompted to "press V to get up") - "V" key (I believe it was changed into Space recently, or it is planned to be changed in the next update)
Spamming A & D is needed during struggle minigame
If the enemy grabbed the character for good, then no more struggling, just watch or press Space to skip the scene.
EDIT: Oh, I see that the full controls are hidden under "Developer Notes" spoiler in the first post.