Panel one: this is one of the first maneuvers Black Fist enforcers get taught. Panel two is how you use that to your advantage as a mage facing an enforcer who is two sure of themselves.

↓ Transcript
<The Baroc thug runs into the room, towards Katharina. She tries to push him back but the thug leans into it to shove back>
Baroc thug: HRNG! Can't get me that -
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<Katharina suddenly reduces the force of the first shove and instead attacks the thug's legs, pushing her off her feet>
Baroc thug: - eeAAAAAAASFHH!!
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<Katharina then follows up by pushing the tumbling Baroc out of the door>
Katharina: OUT!!
Baroc thug: <wrapped in her own cloak> Klmfh'sh ... !
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<Katharina continues to slam the door shut with magic>
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<Shara has meanwhile thoroughly stabbed the other thug and is standing up and catching her breath>
Shara: Hfhh ... wow. That wasn't half bad, princess!
Katharina: <continues to hold the door shut with magic> T-thanks - can you now PLEASE untie Jester while I hold this?!
Book: <who is still gagged and tied to a now toppled over chair> ... Yffh phllff ... !