For the mechanics of the Prof bulwark shield ability:
“Spend 5 Mind to place shield on a Target in bleedout to prevent their bleedout count from progressing. Removing shield from the Target ends the effect.”
Do you need to stay holding the shield for the duration of the effect? Or can you release the shield as long as it stays in contact with them, so you could theoretically then use medical skills on them while their timer is paused.